Having not played John Isner in two years, it took Juan Martin del Potro a while to adjust to the hair-raising speed and peculiar trajectory of the 6-foot-10 American's serve.

But once del Potro figured it out, abandoning his initial strategy of fielding the blasts from the baseline and retreating to nearly the spectator seats at the William H.G. FitzGerald Tennis Center, the Argentine steamrolled to his third Citi Open championship, 3-6, 6-1, 6-2.

Washington's hard-court classic was del Potro's first tournament since a gutting five-set semifinal defeat at Wimbledon last month. After seeing the caliber of the players in the Citi Open's 48-player draw, del Potro dismissed any thought of winning the title in his first test after the extended break.

But he improved with each round. And by Sunday, despite getting to bed at 3 a.m. following a Saturday semifinal that stretched past midnight, del Potro manhandled Isner, who ran out of energy and tactics roughly 30 minutes into the match. It was his ninth match in the past 11 days.

"I wish I felt a little bit better out there," said Isner, 28, now a two-time runner-up in Washington. "At the same time, I could have been 100 percent and clicking on all cylinders and still not have won that match.

"That just speaks to how good a player he is."

In the women's final, Slovakian Magdalena Rybarikova rode consistent composure to a second straight Citi Open title with a 6-4, 7-6 (6-2) victory over Andrea Petkovic. Rybarikova has never lost a Citi Open match.

"It's a great city, and I love to play here — I would like to play all of them here," said Rybarikova, who has four WTA titles. "I feel so good here. I like playing here in the stadium in front of this crowd."

NOTE: Earlier Sunday, the unseeded tandem of Julien Benneteau of France and Serbia's Nenad Zimonjic won the men's doubles title, 7-6 (5), 7-5, over American Mardy Fish and Radek Stepanek of the Czech Republic. Benneteau-Zimonjic won all four of their matches en route to the title in straight sets.