Gallacher (71) finished with a 22-under total of 266 to take his second European Tour win and the first since 2004. The 111th-ranked Scotsman had a three-shot lead over Sterne at the start of the final round but three-putted to bogey the first, and then hit his drive far right and missed a six-footer to drop a shot on the next hole. Sterne chipped to two feet on the second for a birdie and a share of the lead.
The two traded places several times after that as each struggled in windy conditions. Sterne took the lead on the eighth hole when Gallacher missed an 8-foot par putt and found more trouble on No. 9 when his tee shot landed on sandy rough behind a tree. But Gallacher hit a blind approach 185 yards— perhaps the shot of the tournament — that cleared the trees and landed to within two feet for an easy birdie to draw level with the South African.
"I had a window of four foot and I had to cut it, hit it under the first tree and over the next tree," Gallacher said. "When I came out, I saw it was two foot and I couldn't believe it. That sort of kept me going and was a catalyst to dig in on the back nine."
Sterne sank a six-foot birdie on the 10th to go back into the lead but then fell apart with four bogeys in his final eight holes. Gallacher took the lead on No. 12 after Sterne's second consecutive bogey and clinched the win with his fifth eagle of the week on 16. He holed a sand wedge from 115 yards that landed a foot from the hole and rolled in to give him a four-shot lead when Sterne had his third bogey.
"I've holed four shots this week but then again you have to do that these days to win," Gallacher said. "The scoring is so low and the players are so good that you need that little bit of magic."
With the win, Gallacher moves into the top 60 of the world rankings and in a strong position to qualify for the World Golf Championships for the first time. He will also get a chance to play the Masters, the one Major he has never played. The 38-year-old Gallacher said he was helped by right knee surgery at the end of last year and inspired by fellow Scotsman and former British Open champion Paul Lawrie who won twice in 2012 at age 43.
"I'm actually on target because my goal was to try to get in the Top 50 when the Ryder Cup points start, because I don't think you've got a chance of getting in the Ryder Cup team if you're not in the Top 50," Gallacher said.
Sterne led the first two rounds and appeared poised to overtake Gallacher for his first win since 2009 but the 165th-ranked South African's short game let him down when it mattered.
"Second place is obviously pretty good, but when you're leading a tournament or tied for the lead, one shot here or there, I'm disappointed," Sterne said. "Everything swung around on 16. I was one shot behind and then 17, I'm four shots behind."
Felipe Aguilar of Chile (69) and Thorbjorn Olesen of Denmark (71) finished five shots back in a tie for third. Eighth-ranked Lee Westwood (68) and Marcus Fraser (67) of Australia were a further shot back in fifth.
With Gallacher and Sterne dropping shots early on, several players attempted to make a run — none more so than Westwood.
Nine shots out at the start of play, the Englishman had three birdies on the front nine including a chip-in on the 7th. He had two more to start the back nine but then hit a poor chip on the 12th for bogey. Westwood started rolling again with two more birdies on Nos. 13 and 14 and narrowly missed a third on the 16th when his approach rolled to within two feet but he missed the putt.
Westwood birdied the 17th to draw within three shots of Gallacher but bogeyed the last after his second shot hit the green and rolled back in the water.
"I thought I needed eagle at least. On 15, I hit the wrong club and was short on 16. 18, I felt like I had to go for it," Westwood said after finishing fifth in his first tournament of the year and the first since moving to the United States in December.
Englishman Steve Webster (70) finished tied for seventh. He had four birdies on his first six holes to move within three shots of the leaders but then chipped over the green and into the water on No. 7 for a triple-bogey to end his chances. Fellow Englishman Tommy Fleetwood (72) double-bogeyed the ninth hole when he went into the water. He never recovered and finished tied for 10th.
Fourteenth-ranked Sergio Garcia, hampered by a left shoulder injury all week, finished in a tie for 17th after shooting 71.Suggest a correction