Less than a month after turning pro, 21-year-old superstar-in-the-making Jackson Koivun has his first win on the PGA Tour.

The former Auburn college star, and San Jose native, beat world No 1 Scottie Scheffler and a host of other big names to seal a record-breaking victory at the 3M Open in Blaine, Minnesota on Sunday, in turn taking home the $1.6 million first prize.

Koivun headed into the final day with a three-shot lead over his rivals, but needed nerves of steel with 12 players, including Scheffler, within six of him at the top of the leaderboard.

Incredibly, though, he proved his ability in remarkable fashion, making five birdies to register a final-round 66 and race away from the chasing pack - also setting a 72-hole tournament record to finish 25-under-par.

The victory marks his first on the PGA Tour in just his third start since turning pro, immediately after a T23 finish at the US Open in June.

Prior to Sunday, Koivun's career earnings sat at just $93,000, but he now adds $1.584m to that, catapulting himself into the international spotlight at the age of just 21.

Not since the likes of Tiger Woods has a player burst onto the scene quite like the Auburn superstar, who recently decided to forgo his final year of college eligibility to join the PGA Tour earlier than initially planned.

He made his debut on July 3 in the John Deere Classic, and just 23 days later has the first trophy of what is likely to be many of a long career.

Koivun's debut PGA Tour win comes at the 13th time of asking, with the young American having made 10 appearances on the tour as an amateur.  

Before the 3M Open, Koivun's best PGA Tour finish had come at the Procore Championship in September, when he finished T4 – a result that didn't earn him any cash given his status as an amateur.

He sat way back in the field in Minnesota heading into the weekend, but produced a barely-believable 10-under-par 61 – including a record back-nine 28 – to propel himself into the lead.

Speaking after the round, he said: 'Obviously 61 is great. Just excited to be able to go out there and shoot my personal best.'

Koivun heads into his professional career having previously been ranked the No 1 amateur player in the world – and now it is clear why. 

While at Auburn, he became the first player in history to sweep all four major collegiate awards in the same year – the Haskins Award, Jack Nicklaus Award, Ben Hogan Award and Phil Mickelson Award.