It will never feel strange for a Tom Izzo-coached Michigan State team to make the Final Four, but with preseason favorites Kentucky, Wisconsin and Duke all meeting gargantuan expectations to reach Indianapolis, the biggest question entering this weekend is obvious: What, exactly, is this Spartans team doing here?

Their best non-conference win was against Marquette, who finished 13-19. They've already lost to Duke by 10 on a neutral floor. According to Ken Pomeroy's ratings, their loss to Texas Southern (ranked 200th) is the fourth-worst by a Final Four team since 2002. They're not nearly as good of an offensive rebounding team as great Izzo teams have been, they're undersized, they don't force turnovers and they're abysmal at the free-throw line.

There were few reasons to believe that Michigan State could advance to the Final Four beyond Izzo's March magic, making him into sort of a Bill Snyder of college basketball, only with better resources at his disposal. Sometimes, the success just seems to defy explanation. And so here the Spartans are, the unlikely No. 7 seed in a group of No. 1s in the Final Four, beating No. 10 Georgia, No. 2 Virginia, No. 3 Oklahoma and No. 4 Louisville to advance from the East Region and set up a rematch with Duke on Saturday night.

All season long, basketball fans have closely paid attention to Kentucky, Duke and Wisconsin, who have national player of the year candidates and NBA draft lottery picks, and who have hung around the top 10 of the polls all season as preseason conference favorites. Michigan State, meanwhile, is the power team acting like a Cinderella.

What happened?

1. Improved defense

There's no one number to point to that Michigan State has suddenly improved to get to this point, but forcing bad shots and forcing misses has clearly played an enormous role, as a decent defense has made just enough improvement to win close games. None of Michigan State's four tournament opponents have cracked 40 percent from the field: Georgia shot 33.3, Virginia shot 29.8 percent, Oklahoma shot 36.4 percent and Louisville shot 35.9 percent. The four opponents have also gone a combined 14-of-59 (23.7 percent) from three-point range, after Wisconsin lit up the Spartans for 13 three-pointers in the Big Ten championship.

"Our defense has been, you know, at another level," Izzo told reporters this week. "I think some of the reasons for that is that Travis Trice has upgraded his a lot, Bryn Forbes has upgraded his a lot. Yet we think after the last two games looking at film we have a lot of improvement we still can make. This team still isn't a finished product. I guess that's the way it's going to be the entire year."

Izzo referred to the Spartans' defense this year as "solid" numerous times, saying that senior Branden Dawson is the closest thing they have to their traditional lockdown defender, and that junior Denzel Valentine is often given the responsibility of guarding the opposition's best player in their traditional man-to-man defense. Their most common lineups feature the 6-foot-6 Dawson as the second-tallest player, with the 6-foot-9 Gavin Schilling and Matt Costello splitting time at center, but despite the lack of size, Virginia coach Tony Bennett said that the Spartans effectively "jammed the lane" and made the Cavaliers work for good looks in their Round of 32 game. Trice has picked up his play on that end part of a phenomenal tournament, and the increased defensive presence of freshman guard Tum Tum Nairn has also helped.

Maybe, then, there is one number to point to that best exemplifies where Michigan State is right now: While it helps that Louisville is a lousy shooting team, the Spartans held the Cardinals to five second-half field goals on Sunday.

2. No more bad luck

The Spartans have played one of the nation's toughest schedules, and while they've lost 11 games, only two have been by double digits (and one of those two was in overtime). While Maryland's run of close-game wins finally ended in the tournament, the Spartans are turning their close-game losses in the other direction. They're 238th in Pomeroy's luck rankings, having lost five of their seven games that went to overtime prior to the NCAA tournament. They lost to Kansas by five, Notre Dame by one in overtime on the road, Maryland by two in double OT and Nebraska by two on the road, among other close games. In several of their losses, they've been awful at the free-throw line -- they finished 336th in free-throw percentage during the regular season -- which is something that can certainly come back to beat them again in the NCAA tournament but also can be viewed separately from the rest of the on-court product.

"I think when you lose a lot of games shooting 55 percent from the line, about four different losses, when you played in seven overtime games up 'til [Sunday], you lost five of them, that means you were right there," Izzo told reporters on Monday. "You can look at it like, 'Well, better coaching, better play would get you to win those close games.' I thought we did a heck of a job just to get in those close games early on when we were messing with our lineup and we had a lot of injuries early."

In the overtime win over Louisville in the Elite Eight, they shot a solid 15-for-20 from the line, one of their best performances of the season. Trice, a 71.6 percent free-throw shooter, has hit 15-of-16 from the line the last three games, while Valentine hit 6-of-6 against Georgia.

And, in terms of injuries, while the loss to Texas Southern was ugly no matter who the Spartans put on the court, it was the first game without Dawson after he suffered a wrist injury. Remember, Wisconsin has gotten a pass for its loss to Rutgers -- who's rated worse than Texas Southern by KenPom -- with Frank Kaminsky out and Traevon Jackson getting hurt during the game.

3. How the Spartans compare to their past Final Four teams.

The first three times Michigan State made the Final Four under Izzo, it entered the NCAA tournament as a No. 1 seed. Three of the last four times, it's been a No. 5 or, now, worse. This year is the first time it's not been ranked in the AP poll at the end of the season, and it's also easily the worst offensive rebounding team of the bunch to make the Final Four.

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"They're more similar than they are different," Oklahoma coach Lon Kruger said before the Sweet 16. "[Izzo's] club has always had the reputation of really getting the ball down the court quickly. You've really got to do a good job in transition defensively. And yet if you do that, they're still able to change gears and then execute very well on the half-court. This club can do that.

"They've always had a reputation for rebounding the ball well. This club maybe is not as big as some of his teams, but they're very aggressive on the boards. And then defensively, very solid man defense. They don't get real extended, but they don't give up things easy. They make you earn everything. Ask me that about Tom's club 15 years ago, I probably would have said the same things. So pretty similar."

The playing style may be similar, but everything just seems to be a step down this year. But it's not been that bad. They shoot well from everywhere on the floor, avoid turnovers fairly well, are still a decent rebounding team and move the ball to get good looks (only eight teams have a higher assist rate).

What's next?

1. Connecticut provides a recent precedent.

The parallels to last year's UConn team, which won the national championship, are rather amazing, as underperforming third-place teams in their conferences that entered the NCAA tournament as seven seeds and got hot at the right time.

"I think my favorite guy in America right now is Kevin Ollie," Izzo said on Tuesday of the UConn coach. "I love Kevin Ollie. I hated him last year at this time, but I love him now. I think he's kind of shown us the way. He took a team that had struggled at the end of the year. We actually didn't struggle at the end, we were in the middle. He got on a roll, had a guard that took control. Kevin did a great job, not only beat us, but went on to win a national championship as a seven seed. But can history repeat itself? You never know."

Travis Trice hasn't quite taken over the tournament like Shabazz Napier did for the Huskies -- Napier scored 25 points to knock Michigan State out of the Elite Eight last year -- but he has hit some big shots, averaged 20 points per game, improved at the free-throw line and upped his performance on the defensive end to help fuel the Spartans' run. For a team that has lost so many close games, sometimes small improvements can make all the difference, and Izzo's the type of coach who, especially with veteran players, can get those small improvements.

2. Comparing Michigan State to past Final Four outsiders.

Since the NCAA tournament expanded in 1985, 11 teams seeded seventh or worse have made the Final Four: 1985 Villanova (8), 1986 LSU (11), 2000 Wisconsin (8), 2000 North Carolina (9), 2006 George Mason (11), 2011 Butler (8), 2011 VCU (11), 2013 Wichita State (9), 2014 Connecticut (7), 2014 Kentucky (8) and now 2015 Michigan State (7).

Of those teams, 1985 Villanova and 2014 UConn won national championships, 2014 Kentucky advanced to the final and 2011 Butler won a semifinal against fellow underdog VCU to advance to the final. The other six were one-and-done in the Final Four. Michigan State's road has become much more familiar lately, with the run of mid-major Cinderellas for several years, and now the late-blooming power conference teams the last two, starting with UConn beating Kentucky.

"I don't know what seed we should have been," Izzo said. "It's not like it should have been a lot higher. We earned our keep at the end of the year, but we kind of created our own problems in the middle of the year. Some of it wasn't our fault. There were some injuries, some things we talked about. It really doesn't matter." 

3. How Michigan State matches up.

The Spartans are already 0-3 against Final Four teams Duke and Wisconsin. They lost 81-71 to Duke in the Champions Classic in Indianapolis on Nov. 18, and they lost 68-61 at Wisconsin on March 1 and 80-69 in overtime vs. Wisconsin in the Big Ten tournament final. It's safe to say that, given their size disadvantage and play throughout the season, they'd also be significant underdogs against Kentucky in a hypothetical national title game. In fact, size will be a key storyline all weekend, with most of the best players standing taller than most of the Spartans at 6-foot-8 or more: Duke's Jahlil Okafor; Wisconsin's Frank Kaminsky, Nigel Hayes and Sam Dekker; and Kentucky's Willie Cauley-Stein, Karl-Anthony Towns, Dakari Johnson and Trey Lyles.

While this is a historically great Final Four with blue-blood programs and phenomenal coaching talent, Michigan State is the clear outlier. It was off the radar and unranked much of the season, and unlike the other three, it doesn't have highly coveted NBA talent. It seems impossible that this team advanced farther than last year's despite losing Adreian Payne, Keith Appling and Gary Harris and not bringing in high-end instant-impact freshmen.

"Probably back around the beginning or early in February is when I said, 'This team has a chance to make a run,'" Izzo said. "Did I think it would be this deep a run? No, I can't say I did. But I'm very proud. That's what makes me prouder of them. They even surprised me a little bit."

Advancing any farther would undoubtedly be an even greater surprise. Duke is playing at a very high level, drastically improving its defense to pair with one of the nation's best offenses, with stars like Okafor, Justise Winslow, Tyus Jones and Quinn Cook. Michigan State has a 30 percent chance to beat Duke, according to Ken Pomeroy, and only a seven percent chance to win the championship, according to FiveThirtyEight.

This is, however, a single-elimination tournament, and in a single-elimination tournament the best, most deserving team doesn't always win. Michigan State has gotten this far by forcing bad shots and reducing its own mistakes, behind a veteran core that has played a lot of tournament basketball. It's already beaten the odds by getting here, so dismissing the possibility of the run continuing would be foolish. We'll just have to see if some of Izzo's March magic works in April too.

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Contact Matt at matt.brown5082@gmail.com and follow him on Twitter @MattBrownCFB.