DELRAY BEACH, Fla. (AP) — Edouard Roger-Vasselin upset top-seeded John Isner after Ernests Gulbis knocked out second-seeded Tommy Haas on Saturday to set up an unlikely final in the Delray Beach International Championships.

Roger-Vasselin beat Isner 6-4, 4-6, 6-4 in the late semifinal, fending off 21 aces. Isner but could never find his form against Roger-Vasselin, who was playing in his first career ATP World Tour semifinal.

"He beat me," Isner said. "I didn't bring it. It all started with my serve. I didn't make enough first serves.

"Credit to him, he played well and deserved to win. It's very disappointing."

Roger-Vasselin was 0-5 in career quarterfinals. His father, Christophe, was a French Open semifinalist in 1983 and ranked as high as 39th.

"It's a strange feeling because I was not supposed to come here but I got in at the last minute," Roger-Vasselin said. "I couldn't imagine I would be in the final at the end of the week.

"I knew on Friday at 5 o'clock that guys pulled out and that I was in. I was still in France."

Roger-Vasselin had a lead in all three sets, choosing to challenge Isner by playing straight into the 6-foot-9 American's body. Isner was able to rebound from 4-2 down in the second set to even the score at one set apiece.

In the third set, Roger-Vasselin immediately took control by breaking Isner's serve in the first game.

Gulbis, who won the championship here in 2010, beat Haas of Germany 6-3, 4-6, 7-6 (2). Ranked 109th in the world, Gulbis moved into a tournament final for the first time since 2011, when he won in Los Angeles.

"He's very talented and had a huge serve," Roger-Vasselin said of Gulbis. "The key will be like today to make pressure on his second serve."

Gulbis is the fifth qualifier to reach the Delray Beach finals. The others were Marinko Matosevic of Australia (2012), Evgeny Korolev of Uzbekistan in 2009, Kei Nishikori of Japan in 2008, Alex Calatrava of Spain in 2000 and Andrew Ilie of Australia in 1998.

Nishikori and Ilie won the titles when they reached the final.

"It is the first outdoor tournament after the indoor season," Gulbis said. "Qualifiers have one small advantage as they've played already three matches while the main draw guys haven't played a match yet.

"That's why there's a lot of upsets here."

It was another chilly day in South Florida and the wind was swirling at 24 mph during the first two sets. In the third set, as the wind died down to 14 mph the quality of the tennis picked up.

"The beginning was tough and it's not easy to play in those conditions," Haas said. "When it becomes that windy you're whole game plan, whole mood changes and you have to play different tennis.

"In the third set the wind was much better."

Gulbis is known as a talented player who has never found consistency in his game. He's also known for losing his temper when matches aren't going his way.

On Saturday against Haas, he competed to win in adverse conditions and didn't lose focus.

"There is no old Ernests," said Gulbis, who laughingly addressed his better attitude. "Experience. (It's) when you lived a quarter of a century."

Haas is known for having an effective serve, but with the windy conditions he only posted one ace and an uncharacteristic nine double faults.

Haas had opportunities to take control of the third set, but wasn't able to capitalize on his chances. The German had two break points on Gulbis' serve in the ninth game and three break points in 11th game as well.

"I definitely put myself in position to win the match but just didn't do it," Haas said. "If I had won one of those (break points) I think I'd have had the match in my favor."

Gulbis dominated the tiebreaker, securing two minibreaks: a forehand drop shot on the third point and when Haas netted a backhand on the seventh point.