Andy Roddick of the US returns the ball to Spain's Rafael Nadal during their quarter-final match at the ATP Dubai Tennis Championships March 6, 2008.Roddick wins Nadal by 2-0. (Xinhua/Reuters Photo)

Andy Roddick scored a big-serving upset over Rafael Nadal in the quarterfinals of the Dubai Tennis Championships, then announced he had split a week earlier with coach Jimmy Connors.

Roddick used his strong serve to beat the second-seeded Nadal 7-6 (5), 6-2, on Thursday before revealing that Connors had resigned about a week ago because he wanted to spend more time with his family.

"I still have the utmost respect for Jimmy and thank him for his time," Roddick said.

He credited the eight-time grand slam champion for having greatly improved his backhand and boosting his "fighting spirit".