Derik Queen put the Maryland Terrapins on his back and hit a game-winning shot to punch their tickets to the Sweet 16 ... and he tells TMZ Sports the best part about it is he was there for the seniors when they needed him most.

We caught up with the star of Sunday's action after Maryland beat the Colorado State Rams in a nail-biting 72-71 victory in the second round of the NCAA tournament ... and Queen was still riding high off the outcome a day later.

In case you missed it, the 20-year-old freshman got the ball with 3.7 seconds left in the contest ... and drove to the hoop to sink a TOUGH bank shot with the entire season on the line.

After the game, it was revealed Queen told coach Kevin Willard he wanted the ball ... and he told us he was fully confident he could execute -- and the whole team believed it as well.

Queen said the Terps have a ton of team chemistry ... so if anyone else had spoken up ahead of the final play, there would have been full faith in that guy, too.

The Terps are now slated to face off against No. 1 Florida ... and he said his teammates are locked in with hopes of pulling off the upset.