Australia’s Alex de Minaur has breezed through to the next round of the Washington Citi Open, defeating Steve Johnson 6-4 7-5.

The 19-year-old world No. 72 hit five aces to overpower his American opponent and will now face South Korean eighth seed Hyeon Chung for a spot in the quarter-finals.

But fellow Australian James Duckworth was bundled out of the tournament after falling in straight sets to Stefanos Tsitsipas.

The world No.654 went down to the 10th seeded Greek 6-3 6-4 in just over an hour.

Brothers Alexander and Mischa Zverev faced each other in their first ATP main-draw match on Thursday, with No.1 seed and defending champion Alexander getting the win, 6-3 7-5.

Alexander now advances to the quarter-finals where he’ll face the winner of the battle between Canadian Denis Shapovalov and Japan’s Kei Nishikori.

The brothers had met twice before in qualifying matches, most recently in 2014, but never during the actual rounds of a tournament.

The match ended with a lengthy embrace between the pair.

“It was just fun,” Mischa said. “That’s all I can say.”

Their moment as adversaries didn’t last long – shortly after the singles match they headed to a different court and backed up for a 6-1 6-4 win against top doubles seeds Oliver Marach and Mate Pavic.

In other action in the US capital, Wimbledon semi-finalist John Isner was beaten by Noah Rubin while brothers Alexander and Mischa Zverev faced each other in an ATP match for the first time.

A weary-looking Isner was broken twice in the opening set to lose 6-4 7-6 (8-6) to Rubin, ranked 152nd in the world.

Isner was coming off a title in Atlanta last week before facing up against Rubin in the all-American matchup.

Rubin will now meet Russian Andrey Rublev in the next round.