Antalya, Turkey (SportsNetwork.com) - Brooks Koepka fired a 7-under 65 in Sunday's final round and rallied to win the Turkish Airlines Open by one stroke over Ian Poulter.

Koepka finished his first European Tour victory at 17-under-par 271. His eagle at the 13th gave him the outright lead for the first time in the final round, and he held on from there.

"It means so much. To work my way up from the Challenge Tour and to win on the European Tour, it's special. I've been waiting for this win for a while now," admitted Koepka. "It's nice to have it here. It was an unbelievable field and to win here is special."

Poulter, who led by six after two rounds, carded a 5-under 67 in the final round to end at minus-16.

Seven different players had a piece of the lead at different points on the front nine at The Montgomerie Maxx Royal. The final nine was a battle between Koepka and Poulter.

Henrik Stenson, who won the Race to Dubai last year, fired an 8-under 64 for the low round of the day. He ended alone in third at 14-under-par 274.

First-round leader Miguel Angel Jimenez (68), Andy Sullivan (67), Danny Willett (69) and Wade Ormsby (71) shared fourth place at minus-13.

Rory McIlroy officially clinched this year's Race To Dubai title without playing the first three events of the finals series. Marcel Siem, Sergio Garcia and Jamie Donaldson could have moved past McIlroy and won the Race, but all three needed to win this event and next week's title as well.

Siem had the best finish of the three, as he closed with a 71 to finish tied with Lee Westwood (71) for eighth place at 12-under-par 276.

Koepka birdied the third and fourth to move to 12-under. That was his fourth birdie in four days at the par-5 fourth. When Siem, who played alongside Koepka, also birdied the fourth, that created a six-way tie for the lead with Willett, Westwood, Ormsby and Poulter.

Poulter opened with a birdie at the first and he also birdied the fourth for the fourth round in a row. His birdie on No. 4 moved him alongside Koepka and Ormsby at minus-13 as Koepka made his third birdie in row at the fifth.

Poulter again moved one ahead as he converted a 5-foot birdie putt at the sixth, but Koepka answered with a 3-foot birdie effort at the eighth.

They traded birdies again as Poulter moved to 15-under with a 12-foot birdie putt at No. 9. Koepka poured in a long birdie try at 10 to join Poulter atop the leaderboard.

The 13th proved to be the difference. Koepka, who was one group ahead of Poulter, made eagle to jump to 17-under. Poulter found a greenside bunker with his approach and got up and down for birdie, but was one back.

Koepka hit a tree with his approach at 15, but got up and down for par from the thick rough. His second shot at 17 soared over the green as he was distracted by something the crowd.

The American gathered himself and got up and down for his par. Koepka pushed his drive into the right trees at 18 and chipped back into the fairway. He found the green with his third, but 2-putted for a closing par.

"I just stayed patient. I stayed pretty calm. Making some key putts helps just calm everything down and relax a little bit. I think that eagle on 13 was really big for me. Especially the last few holes because it builds momentum going in, and those par saves were pretty good," Koepka stated.

That left it to Poulter. The Englishman saved par from a greenside bunker at the par-3 16th. He also parred 17 and headed to the last down by one, then found the fairway off the tee.

However, his approach shot faded into a bunker right off the green. Poulter hit a solid bunker shot to six feet, but handed the crown to Koepka as he missed the putt on the left despite watching Westwood putt from a similar spot.

"It was probably a bad thing that I stood there and watched Westy's putt, because I think he pushed it slightly and it fell in the right edge," said Poulter. "I knew my putt was going to break right to left. I hit it what I thought was right edge, with decent pace, and it broke across the hole. I don't know whether he pushed his too much or whether I read too much in that. It might have been better if I hit my putt first."

NOTES: Koepka earned 1,666,600 euros for the win and he will move inside the top 40 in the world rankings after starting the week No. 61 ... Koepka was the 12th first-time winner this season on the European Tour ... The tour will be in Dubai next week for the season-ending DP World Tour Championship, Dubai, where Stenson cruised to a six-stroke win last year.