Days after his rare win as an amateur on the PGA Tour, Nick Dunlap announced Thursday that he is turning pro and accepting membership on the tour.

With his victory Sunday at the American Express, Dunlap became the first amateur to win on tour since Phil Mickelson in 1991. The 20-year-old is only the fifth amateur to win on tour since 1950 and the second-youngest champion in the past 90 years. Jordan Spieth won the 2013 John Deere Classic when he was 19.

“It was the easiest, hardest decision that I’ve ever had to make,” Dunlap said Thursday. “I was very fortunate that everyone had the same opinion about it, and my teammates were awesome and very supportive. It goes back to the family that Alabama has. They were very supportive and wanted me to chase my dreams.”