MASON, Ohio, Aug 16, (Agencies): Seventh-seeded Gregor Dimitrov defeated Feliciano Lopez 7-6 (5), 6-4 on Wednesday to reach the Western & Southern Open’s round of 16. Sixteenth-seeded Madison Keys easily reached the women’s round of 16 in Cincinnati for the first time on her fourth try, needing just 50 minutes to zoom past Daria Kasatkina 6-2, 6-1.Keys, a right-hander who withdrew from last week’s Rogers Cup in Toronto with a left forearm injury, next will meet fourth-seeded Garbine Muguruza, the Wimbledon champion.After being forced to a tiebreak in the first set, Dimitrov raised his level of play in the second with 13 winners to Lopez’s four. Dimitrov finished with 28 winners, twice as many as Lopez.Other seeded women reaching the third round were eighth-seeded Svetlana Kuznetsova, with a 6-3, 6-4 win over Yulia Putintseva, and Anastasija Sevastova, with a 6-2, 7-5 win over Roberta Vinci.In a week where most ATP stars are idled by injuries, the two men with multiple titles since Wimbledon — John Isner and Alexander Zverev — are on a collision course.Isner fired 16 aces and needed only 56 minutes Tuesday to dispatch fellow American Tommy Paul 6-3, 6-3 and reach the third round at the ATP and WTA Cincinnati Open.World number 19 Isner, who won titles last month at Newport and Atlanta, could next face Zverev, who has taken titles the past two weeks at Montreal and Washington, although the 20-year-old German must get past US teen Frances Tiafoe on Wednesday.World number 10 Milos Raonic of Canada withdrew Tuesday with a left wrist injury, leaving only three of the top 10 in the men’s field.Also among the missing are Roger Federer (back), British world number one Andy Murray (hip), Novak Djokovic (elbow), Stan Wawrinka (knee), Kei Nishikori (right wrist) and Marin Cilic (adductor).That offers an enticing chance for those who have never won so large a title, even with Zverev and Nadal still in.“It’s an opportunity for a lot of players,” Isner said. “I think (Zverev) recognizes that as well. I think he has looked at the draw and seen that Roger is out and Milos is out.“So I think his eyes are kind of popped wide open again. He’s looking for another one.”On the women’s side, Wimbledon winner Garbine Muguruza, and second-ranked Simona Halep cruised into the third round.Romania’s Halep, hoping to overtake Czech Karolina Pliskova for the world number one ranking this week, downed US qualifier Taylor Townsend 6-4, 6-1, while Spain’s sixth-ranked Muguruza ousted Brazil’s Beatriz Haddad Maia 6-2, 6-0.“I’m happy to be into the third round,” Muguruza said.After trading four service breaks in the first six games, Halep took 11 of the last 12 to dispatch Townsend in 66 minutes.US ninth seed Venus Williams downed compatriot Alison Riske 6-2, 6-0 to book a second-round match with Australian qualifier Ashleigh Barty.French Open champion Jelena Ostapenko of Latvia was ousted by Serbian qualifier Aleksandra Krunic 6-4, 6-2 while Russian lucky loser Natalia Vikhlyantseva beat Croatia’s Donna Vekic 6-3, 2-6, 6-3 to book a matchup with Czech women’s world number one Karolina Pliskova.