At just 21 years old, and only 24 days as a professional golfer, Jackson Koivun can call himself a PGA Tour winner.

And he held off Scottie Scheffler, the world No.1 golfer, to do it at the 3M Open on TPC Twin Cities in Minnesota on Sunday.

Koivun shot 5-under in his final round to shoot 25-under to win the tournament, while Scheffler’s 8-under final round wasn’t enough as he finished three strokes behind a golfer that could become a household name quite soon.

Koivun propelled himself into prime position to win the tournament when he posted a 10-under 61 on Saturday in Round 3 to move to 20-under for the tournament. It was a tournament record during the round, too, as his 28 on the back-nine was the best score ever posted in those holes.

It was clear he was focused on winning it all during his final round, especially after going 3-under through his first six holes on the day.

Koivun would post two birdies on the back-nine, and finish with a bogey-free final round to put the icing on his breakout tournament of his very early PGA Tour career.

Now, after becoming a pro earlier this month, Koivun just cashed a $1.584 million check for winning what he hopes will be the first of many PGA Tour events.

"All throughout the crowd, I kept hearing, ‘Scottie’s coming, Scottie’s coming,’" Koivun admitted after his victory on the CBS broadcast. "I just tried to tone that out and keep playing the golf I knew I could."

It’s hard to block out when Scheffler’s climbing a leaderboard because it usually ends in his favor. After going 3-under on the front nine, Scheffler turned his putter into final-round gold on the turn, draining birdie putts on the first three holes of the back-nine. He cooled off, if you wish to call it that, before birdying two of his final three holes to give himself a chance.

Koivun didn’t blink, scoring par on his final two holes including the Hole 18 par-5, where he understandably pumped his fist after draining a final par putt to seal victory.

Winning isn’t anything new for the now-former top amateur in the world, but it’s a different feeling when it’s on the PGA Tour for the first time.

"I just love this game. I love golf, it’s everything I do. I have a tough time getting away from it," he explained. "…It’s been love at first sight."