Zverev and Kuznetsova earn Citi Open championships

Alexander Zverev's second Citi Open title in a row is merely the latest sign that he is separating himself from the other up-and-coming youngsters in tennis.

That doesn't mean he is sure that guys such as Roger Federer or Rafael Nadal are worrying just yet.

"You've got to ask them. I don't think Roger's too concerned about it," Zverev said with a smile. "He's somewhere in Switzerland right now, enjoying ... his milk from his cow."

Zverev became the first man in nearly a decade to win consecutive titles at Washington's hard-court tuneup for the U.S. Open, overpowering Alex de Minaur 6-2, 6-4 in the final Sunday.

Juan Martin del Potro won the Citi Open in 2008 and 2009.

Zverev hit six aces, and never faced a break point en route to his ninth career ATP title and third of 2018. "He hit me off the court today," de Minaur said. Two-time major champion Svetlana Kuznetsova won the women's final, erasing four match points in the second set on the way to a 4-6, 7-6 (7), 6-2 victory over Donna Vekic. Kuznetsova also won the title in Washington in 2014.

Germany's Zverev is 21, and Australia's de Minaur is 19, making for the youngest final on the ATP World Tour since 20-year-old Rafael Nadal beat 19-year-old Novak Djokovic at Indian Wells, California, in 2007.

Kuznetsova won her second title at the Citi Open, and first at any WTA tournament in two years, by erasing four match points to beat Vekic.

The No. 7 seed Vekic was one point from victory four times in the second set but was not able to close it out.

Kuznetsova is a two-time Grand Slam champion, but she is currently ranked only 128th, the lowest spot for a women's champion at the hard-court tournament.