Top seeded Juan Martin del Potro will face American John Isner for the Citi Open title after both posted victories in their semifinal matches on Saturday.

Del Potro outlasted third-seeded Tommy Haas as well as a three-hour rain delay to run his Washington winning streak to 13 matches, with the Argentinean earning a 7-6 (7-4), 6-3 victory.

The 24-year-old will appear in his third final of the year and is aiming for his third Citi Open title. He won the event in 2008 and 2009.

Isner, fresh off last week's title at the BB&T Atlanta Open, ran his current win streak to eight games with a 6-7 (7-9), 6-3, 6-4 victory over Russian Dmitry Tursunov in a match that was delayed for over an hour due to rain.

The towering American ripped off 29 aces, including six straight to close out the match, to advance to his 15th career ATP Tour final. Isner was the runner- up to Andy Roddick in this event in 2007.

The 2013 Citi Open champ will collect $292,200.