James Blake beat fellow American Mardy Fish 7-5 6-4 on Saturday to win the Pilot Pen tournament in New Haven.
Blake also won in New Haven in 2005
Blake was playing in his second final in a week having lost to Roger Federer in Cincinnati last Sunday.
Top-seeded Russian Svetlana Kuznetsova won the women's event when Hungary's Agnes Szavay pulled out with a back injury in the second set of the final.
The unseeded Szavay won the first set 6-4 but fell 3-0 behind in the second before announcing her retirement.
Kuznetsova claimed her first title of the year and the ninth of her career.
It was the third straight match that Kuznetsova had won after her opponent retired through injury or illness.
Kuznetsova won her third-round match when Francesca Schiavone dropped out with an ankle injury and advanced to the final when Elena Dementieva had a stomach ailment in
"It's a bit strange but the only thing I can say is that in most of the matches I was winning," she said of her run against opponents who quit matches.
"Today was the closest I was to losing, but I was getting my game back and then she retired. I cannot change it.
"When I saw she was calling for the trainer, I was like, no, please," Kuznetsova added.
"I felt really sorry for her. She was playing so well and the US Open is coming. I hope she can recover."
Szavay was playing her eighth match in nine days and had been battling back problems most of the week.
"At the beginning it was just a little muscle pain and nothing serious, but day by day it was worse and worse," she said.
In the men's final there were five breaks in the first set as close friends Blake and Fish struggled with their service games.
But up 6-5 after a break, Blake found his serve, won the set and quickly went 4-1 up in the
second. Fish fought back to 3-4, but could not level.
"This might be bragging rights for a while," Blake said. "It's tough, because you really want to see him doing well too."
Fish said it might have been a case of knowing his friend's game too well.
"You think they know what you're going to do, so you know that they think you know what they're going to do, and you kind of outthink yourself a little bit," he said.
Argentine third seed Gisela Dulko had a 6-2 6-2 victory over top seed Virginie Razzano of France in the final of the pre-US Open Forest Hills Classic.