Juan Martin del Potro may soon be celebrating a career quinceañera…

The 24-year-old Argentine tennis player – the top seed at Washington, D.C.’s Citi Open – beat third-seeded Tommy Haas 7-6 (4), 6-3 in the semifinals Saturday to earn a chance to claim his fifteenth career ATP title.

del Potro stretched his winning streak at the hard-court tuneup for the U.S. Open to 13 matches. He claimed the title at the Washington tournament in 2008 and 2009, then skipped it the past three years.

Trailing Haas 4-1 when a downpour caused a three-hour delay in play, 2009 U.S. Open champion stormed back to win four games in a row.

“The rain delay’s annoying. It bothers me a lot, actually,” said Haas, who showed frustration at various moments by spiking, tossing or kicking his racket. “Come back out there, and the momentum was really on my side, at least for the first set, I think. (If) it would have been mine, it would have been maybe a different match. But these are all the ‘ifs’ and ‘buts’ and not worth talking about.”

Still, Haas actually held two set points late in the first, one of which del Potro erased with a 117 mph second-serve ace, and the other with a volley winner.

“He went for it,” said Haas, a finalist last year. “He deserved it.”

del Potro now faces John Isner in the finals on Sunday.

“Nobody can break his serve in this tournament. … Of course, sometimes you get frustrated when you can’t return his serve,” said del Potro, looking ahead to facing Isner.