WASHINGTON: Reigning US Open champion Emma Raducanu of Britain advanced to the quarter-finals of the ATP and WTA Washington Open, refusing to wilt Thursday after a marathon match in sweltering heat. The English 19-year-old outlasted Colombia’s Camila Osorio 7-6 (7/5), 7-6 (7/4) after two hours and 50 minutes for a gritty victory in the WTA’s longest two-set main draw match of the year. “It has got to be one of the most physical matches I’ve ever played,” Raducanu said. “It was a pretty monumental effort to really get through that. “I’m just really pleased and proud of how I dug in when it really mattered. It just gives you a lot of confidence coming through a match like that. “Physically, I’m pretty pleased with how I held up in that match. Looking forward to going again.” Raducanu advanced to a Friday quarter-final against Liudmila Samsonova, who rallied past Australian Ajla Tomljanovic 4-6, 6-3, 6-2 at the US Open tuneup. It will be only Raducanu’s third quarter-final since her amazing Grand Slam title run last year at New York, having reached the last eight at Cluj-Napoca last October and Stuttgart in April. She has yet to reach a semifinal since taking the trophy last September at Flushing Meadows. “Sometimes in your career you feel like everything is automatic, you can go for whatever shot you want and it’s going to land,” Raducanu said. “Those weeks don’t come by very often. I’ve just accepted I’m not going to feel like that every week.” Osorio trailed Raducanu 3-0 but broke back in a 13-minute seventh game and broke again to lead 5-4, then had three double faults serving for the first set, one on set point, and Raducanu broke back. In the first tie-breaker, Osorio won five of six points, the last when Raducanu double faulted, to seize a 5-3 edge. But Raducanu won the next four points, the last three on forehand winners, to capture the set. “Mentally I’m really proud of how I’m doing right now,” Raducanu said. In the second set, Raducanu broke with a forehand volley winner for a 2-1 lead but needed treatment for blisters on her left foot and Osario battled back to force a tie-breaker. Raducanu took five of the final seven points for the triumph, the last on a service winner. “I most enjoy the challenge of continuously coming back and getting back up, getting yourself out of rock bottom a lot of times repetitively,” Raducanu said. “It’s a fun challenge and I’ve twisted my perception of it. I’m not viewing it as a negative thing anymore. “The reward that you feel after a win, knowing you’ve come through that, it means a lot more.” On the men’s side, British 16th seed Daniel Evans advanced to the last eight when US third seed Taylor Fritz retired with the Englishman leading 3-6, 7-6 (8/6), 4-1. Next up for Evans is world number 96 Yoshihito Nishioka of Japan, who edged seventh seed Karen Khachanov 7-6 (7/2), 7-6 (7/1). Nishioka is 4-0 all-time against Evans, including a 2019 first-round win at Washington, a 2020 Australian Open second-round victory and a win at Miami in March.