INCHEON, South Korea — Curtis Luck overcame a seven-stroke deficit to win the Asia-Pacific Amateur on Sunday and earn a Masters invitation that the Australian didn’t need.

Already in the Masters with his U.S. Amateur victory, the 20-year-old Luck made a 15-foot birdie putt on the par-5 18th for a 5-under 67 and a one-stroke victory over countryman Brett Coletta.

“I’ve had an amazing year and this has topped it off,” Luck said. “I came here to try my best and win, but I wasn’t expecting to be standing here with the trophy at the end of the week.”

Luck finished at 12-under 276 at Jack Nicklaus Golf Club. He earned a spot in the British Amateur, after securing positions in the Masters, U.S. Open and British Open with his U.S. Amateur victory in August at Oakland Hills.

Coletta, the third-round leader, had a chance to force a playoff on 18, but missed a 14-foot birdie try.

“It was a pretty nerve-racking finish,” Luck said. “I knew Brett could make birdie on 18, so fortunately for me he didn’t. That bunker shot was probably one of the most nervous shots I’ve ever had to play, and the putt just topped it off. I left myself a bit of a swinging putt, but I had a really good feel for it.”

Luck ended up costing Coletta a spot beside him the Masters.

“Brett’s a really close friend of mine and I understand the opportunity he has just missed out on,” Luck said. “I do feel a little guilty and sad, but I’m so competitive I couldn’t give up the chance to win an event like this.”

Coletta had two double bogeys in a 75.

“It’s really hard to swallow, but you’ve got to look at the positives,” said Coletta, also 20.

New Zealand’s Luke Toomey was third at 9 under after a 66.

Australia’s Cameron Davis, a stroke ahead of Luck and Coletta with four holes to play, closed bogey-bogey-birdie-triple bogey for a 77 that left him fourth at 7 under.

Last week in Mexico, Davis teamed with Luck to lead Australia to victory in the World Amateur Team Championship and topped the individual standings.

The tournament is run by the Asia Pacific Golf Confederation, the Masters and The R&A.