Defending Washington Open champion Alex De Minaur stormed into the quarter-finals with a straight-sets victory over Cruz Hewitt.

De Minaur has seen the development of Hewitt – son of former world number one Lleyton Hewitt – over the years, and produced a clinical 6-2 6-3 victory in the pair's first meeting.

It was an impressive start from De Minaur, who raced into a 5-0 lead at the start of the first set with three consecutive breaks.

Hewitt quickly rallied, though, to convert his third break point and pull a game back before holding serve for the first time, but De Minaur soon got over the line.

The top seed then reeled off three games early in the second set to regain full control.

Hewitt then went toe-to-toe with his opponent but was caught out again in the ninth game; the 17-year-old saved the first two match points on his serve, but De Minaur converted on his third attempt.

"It was definitely weird," De Minaur said in his on-court interview.

"I knew I was going to play him on the Tour some day, but I didn't actually expect it to be this week. It was an amazing feeling.

"Even all the lead-up, seeing all the incredible pictures that we have together and how we've both grown up. I'm glad I managed to get through, but I'm sure we're going to have many battles in the years to come."

The defending champ is moving on @mubadaladcopen | #MubadalaDCOpen | @alexdeminaur pic.twitter.com/anOhTJNCie

— ATP Tour (@atptour) July 30, 2026

De Minaur will face Brandon Nakashima in the last eight after the American held off Jakub Mensik in three sets.

Nakashima upset the seventh seed with a 7-6 (7-5) 3-6 6-4 victory in two hours and 16 minutes to reach the quarter-finals in Washington for the second consecutive year.

De Minaur is finding his groove again

Following a disappointing Wimbledon campaign, De Minaur has taken a short break and come back with a new fire burning.

He improved to 29-14 for the season with this victory, and hit six aces as well as landing 75% of his first serves in (21/28) in a strong performance. He also converted five of the seven break points he forced.

Before the last-16 meeting, Hewitt described De Minaur as an "older brother", and he impressed on his first main draw appearance on the ATP Tour. He could not cause another upset, though, having knocked out Marcos Giron in the previous round.

De Minaur is now set to face Nakashima for the second consecutive year in the Washington quarter-finals – it is the 27-year-old's lone win against the American, who holds a 2-1 record in their head-to-head.