Steve Johnson upset sixth seed Grigor Dimitrov to reach his fourth quarter-final of the season at the Citi Open in Washington on Thursday.
Johnson's 6-3 1-6 6-3 win, avenging defeat to the same opponent at Wimbledon, set up the first all-American quarter-final in this tournament since 2003 as he booked a meeting with Jack Sock.
Sock, seeded 15th, battled his way past number four Richard Gasquet 6-7 (4/7) 7-6 (7/5) 6-4.
"It should be a good battle," Sock told the ATP website of facing Johnson. "We've played a few times now and each won a couple and last time we played was last year's French Open.
"He's playing some pretty good tennis now, he's had some pretty consistent results and moved up the rankings. I think especially on a surface like this and in the US, both playing here, it should be a fun match. I'm just happy there's two Americans advancing."
Teymuraz Gabashvili, who knocked out top seed Andy Murray earlier in the week, saw his run come to an end as he was beaten 7-5 6-4 by Ricardas Berankis.
Berankis will face eighth seed John Isner in the quarters after the American beat number 12 Vasek Pospisil 6-4 7-6 (8/6).
Third seed Marin Cilic reached the quarters after being given a work-out by number 13 Sam Query, eventually prevailing 7-6 (7/2) 7-6 (7/3), and he will next face German Alexander Zverev, who rallied to beat Alexandr Dolgopolov 2-6 6-2 6-4.
Second seed Kei Nishikori beat Leonardo Mayer 6-4 6-4 and will face Sam Groth after the Australian dispatched seventh seed Feliciano Lopez 6-3 6-4.
Source: PA
