It's an age-old question: Was it a pick … or a catch?

The only eight people whose opinions matter --the officiating crew -- said THERE WAS NO PICK!

That answer probably serves as little solace to Alabama fans, as they fell to Clemson, 35-31, in Monday's College Football Playoff national championship game thanks to a touchdown in the final seconds that certainly looked to the untrained eye like a possible infraction.

Twice in the fourth quarter, Clemson took the lead by completing passes at the goal line on what's best known as a pick play (although coaches call it a "rub"). The final one was the winner from Deshaun Watson to Hunter Renfrow.

The play, borrowed from the basketball court, is simple. One receiver runs a route that might "accidentally" impede a defender from following a second receiver on his route, springing him open for a quarterback to deliver what can develop into an easy toss.

Often, officials will throw a flag for offensive pass interference when it happens. In 2014, Notre Dame was beat in a game between top five teams due, in part, to a penalty on a play that was almost identical to the one that gave Clemson its first national title since 1981.

The Irish touchdown was taken off the board and they eventually lost.

So what was the difference? Execution.

Despite what your favorite college football conspiracy theorist might have told you, pick plays are not explicitly illegal. Their purposeful design requires precision and, when run correctly, can produce separation in short yardage situations where space is at a premium.

NCAA rules state that players cannot exhibit "an obvious intent to impede" a defender on a pass play. Here's the rub, though: Officials must decide in an instant whether that intent to impede is obvious or not and do so on a play that can look like it has devolved into disarray. It's a pure judgment call that isn't reviewable, just like holding or defensive pass interference.

On Clemson's first touchdown, tight end Jordan Leggett acts like he's blocking his defender into the end zone, but when he hits the goal line, he immediately stops and turns toward Watson, flashing his hands as if he's waiting for a pass.

Clemson could run that play 5,000 times and Watson would never throw Leggett the ball. But that doesn't matter. Leggett's performing an acting job that's meant to sell the idea he's running a real route and prevent officials from flagging the play.

Leggett never initiates contact with the defender, who is blindsided and falls down when he runs into Leggett's hip, leaving Mike Williams wide-open for the go-ahead score. 

The second, game-winning pick was a little messier, but look closer at No. 3 Artavis Scott from Clemson, who starts on the outside and sets the "pick" for Renfrow.

"I knew if Tay make his block and got the little pick, Renfrow was going to get in the end zone," Watson told reporters after the game. "I kind of smiled, and I knew before I even snapped the ball it was going to be a touchdown. All I had to do was just get the ball to him. I slowed down the moment, everyone made their blocks and did their part, and I did my part, and we pulled it out."

Scott runs in to block Alabama defensive back Marlon Humphrey, but for whatever reason, loses his balance. He never touches the Tide's Tony Brown, who got lost on the play and went under the pick while Renfrow went over. It's the same concept that has freed up Steph Curry for many a three ball over his career.

The Scott-Humphrey dustup provided plenty of chaos and allowed Renfrow separation for a score that will go down in Clemson lore.

The common thread: Neither Leggett nor Scott ever initiates contact with a defender trying to get to the intended receiver. You can't say the same for Notre Dame on its score that got flagged.

Coaches talk on and on about execution. When they do, those little differences are exactly what they mean.