Stefanos Tsitsipas advanced to the Citi Open quarter-finals and the in-form top seed was joined by Marin Cilic and Daniil Medvedev.
Tsitsipas was too good for Australian Jordan Thompson, prevailing 6-3 7-6 (7-4) to book a spot in the last eight on Thursday.
Greek star Tsitsipas saved a set point in the second set as he earned a clash with 10th seed Benoit Paire in Washington.
"It's very pleasing knowing that I can be mature and handle those situations very bravely, so I'm really happy with that," said Tsitsipas.
"I showed character out there. I played heroic tennis, I would say, in those crucial moments. That was very nice to see."
Paire – who fired down 12 aces and did not drop serve – defeated fifth seed John Isner 7-6 (7-3) 6-3 at the ATP 500 tournament.
Former US Open champion Cilic beat ninth seed Felix Auger-Aliassime 6-3 6-4 to reach the Washington quarters.
Auger-Aliassime's 11th double fault of the match allowed sixth seed Cilic to move through, with Medvedev waiting in the next round.
Medvedev – the third seed – saw off local favourite Frances Tiafoe 6-2 7-5.
Elsewhere, eighth seed Milos Raonic was stunned 6-4 6-4 by Peter Gojowczyk, Kyle Edmund rallied past Jo-Wilfried Tsonga 4-6 6-3 6-4, Norbert Gombos trumped Miomir Kecmanovic 1-6 6-3 7-6 (7-4) and Nick Kyrgios was a 6-2 7-5 victor against Yoshihito Nishioka.