Erin Hills in Wisconsin plays this weekend as the longest course in the history of the U.S. Open, and has thick fescue roughs flanking its fairways. But that didn't bother the golfers. What we got was a slew of birdies, and some low scores at the top of the leaderboard after one round, with the leader sitting at -7.

But there are many important names missing from the top. Jason Day's been a disaster at 7-over, Dustin Johnson's chances of repeating are fading at 3-over. Rory McIlroy and Jordan Spieth are barely clinging to hope at two-over and one-over, respectively.

Of course, there is still plenty of golf left, and drama on the way. Here are five golfers to watch during round two of the U.S. Open, teeing off Friday.

Rickie Fowler, -7

Fowler's warmup for the U.S. Open didn't got to plan, missing the cut last weekend at St. Jude Classic. Nevertheless he set a torrid pace in the first round, hitting a 7-under 65, tying a record for lowest score in the opening round of the U.S. Open. That's how you bounce back.

Fowler is perhaps the top name on the list of best golfers without a major to their name. He's finished in the top five of all four, coming in second at the U.S. and British Opens of 2014. It always seems like a matter of when, not if, Rickie wins a major. If he has three more rounds like this one, his name will come off the list on Sunday.

Tommy Fleetwood, -5

Get to know this name. The 26-year-old from the Merseyside has only competed in eight majors up to this point, and missed the cut at the Masters in his last attempt. But with his 5-under 67 on Thursday, he stands ready to make a run for the U.S. Open title this weekend.

Fleetwood and Paul Casey are the highest Europeans on the leaderboard. Along with Lee Westwood, Paul Casey, Andrew Johnston and Matthew Fitzpatrick, he stands among a large group of Englishmen who will compete for a win this weekend. But where you really need to keep an eye on Fleetwood is next month in the Open Championship at Royal Birkdale in his hometown of Southport. This might just be the sneak peek before the grand opening of what is Fleetwood's career among the best in golf.

Patrick Reed, -4

It's only fitting that "Captain America" stays in contention. Reed earned that moniker for his fiery showing for the United States last fall in the Ryder Cup.

In his red, white and blue get-up, Reed played like he did when competing for the American team in the first round. By contrast to his demeanor in the Ryder Cup, though, Reed was cool and collected. He hit 13 greens and 13 fairways. On the ninth hole, he responded with two bogeys in three holes with a birdie to stop the bleeding, then rattled off four more birdies on the back nine.

We'll see if wears America-centric gear again on Friday, and if that helps him stay near the top of the leaderboard.

Davis "Dru" Love IV, -1

Davis Love III is out on the course at Erin Hills this week, just not in the role you'd expect. DL3 is serving as a caddy, toting the bag for his son, Davis "Dru" Love IV. With his famous father on the bag, Love IV made his pro debut, shooting a 1-under 71 at the U.S. Open to kick off his pro career.

It seems doubtful that Love IV can actually mount a challenge to win this weekend, but he could make the cut and make some noise. At the very least, it'll be fun to watch the dynamic between these two as Love IV competes throughout Fathers Day weekend.

Ernie Els, -1

This is one name that would've made fans do a double-take when glancing at the leaderboard during the first round. He shot a one-under 71 on Thursday, 20 years to the day since he won the 1997 U.S. Open at Congressional Country Club, the second and last Open win of his storied career.

With the injuries he's sustained over the past few years, there's a good chance this the final U.S. Open of Els' career. If it is, it'd be great to see him still in the mix, or at least still on the course, on Sunday. He's only finished in the top 20 once in his last 15 majors, so the odds are against him stay near the leaders. But if he does, there's no doubt who the fan favorite will be for the next few days.

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Cy Brown writes about soccer and other stuff for Sports on Earth. Follow him on Twitter @CEPBrown.