Cornell freshman Yianni Diakomihalis went down after the opening minute of his NCAA quarterfinal match, and knew something was wrong.

It was his right knee. He knew it, wincing as he went back to the center of the mat. His coaches knew it. Diakomihalis, though, kept going.

Diakomihalis knocked off two-time NCAA champion Dean Heil, and then kept his run alive, beating Jaydin Eierman and Bryce Meredith to win the 141-pound NCAA title — becoming just the 19th person to do so as a true freshman in tournament history.

After winning the championship, though, a post-tournament MRI confirmed what his trainer had suspected since the quarterfinal match: Diakomihalis had torn his ACL.

“It’s just remarkable. It just shows the kind of kid he is and he wasn’t 100 percent,” Cornell coach Rob Koll told Track Wrestling’s Andy Hamilton on Friday. “But when you get to the national championship, you do what you’ve got to do. We always say, this time of year there are no such thing as injuries. You’re not hurt. No one cares. You’ve got all summer to get healed up.”

Diakomihalis — who finished his first colegiate season with a 34-1 record — is scheduled to have surgery on his knee next week in New York City.

The Rochester, New York, native was apparently, though, trying to keep his injury under wraps — even more than a week after winning his title.

His success even with the injury that sidelines most athletes almost instantly, Koll said, simply comes down to toughness.

“The reality is, all the tape in Russell Athletic won’t get a guy through a tournament if he doesn’t have the toughness,” Koll said. “(Diakomihalis has) done that for the last 15 years of training. That’s what he does every day in practice.”

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