WASHINGTON (AP) — Alexander Zverev is back in the final at the Citi Open.

The defending champion beat 10th-seeded Stefanos Tsitsipas 6-2, 6-4 in the semifinals Saturday. The top-seeded German is looking to become the first back-to-back winner of the hard-court U.S. Open tuneup since Juan Martin del Potro in 2008 and 2009.

Zverev has won 15 of 17 career matches in Washington.

"I'm playing great here," Zverev said. "Hopefully, I can continue to do so (Sunday) and hopefully in the next few years, as well."

Zverev will face Alex de Minaur in the final after the unseeded Aussie beat Russia's Andrey Rublev 5-7, 7-6(8), 6-4 in the other semifinal. De Minaur reached the semis when former No. 1 Andy Murray withdrew from the waterlogged tournament, citing fatigue.

At 21, Zverev was the oldest player in the semifinals along with the 19-year-old Tsitsipas and de Minaur and 20-year-old Rublev. Zverev joked after advancing, "I think I'm the only one that's allowed to buy a drink in the U.S., right?"

Russia's Svetlana Kuznetsova beat Germany's Andrea Petkovic 6-2, 6-2 to reach the women's final. The 2004 U.S. Open and 2009 French Open winner will face seventh-seeded Donna Vekic of Croatia as she looks for her 18th WTA title.

Vekic beat unseeded Zheng Saisai of China 7-5, 6-3 in the semifinals.

Saisai beat American qualifier Allie Kiick 6-3, 6-1 in the quarterfinals as she and Rublev were forced to play twice Saturday. Rublev beat local product Denis Kudla 6-1, 6-4 before losing in three sets to de Minaur.

Rain throughout the week pushed action back and led to Murray exiting the tournament. The three-time major champion, coming back from hip surgery, finished his most recent match at 3 a.m. Friday and decided to withdraw rather than play again so soon afterward.