Juan Martin del Potro made a winning return at the Cincinnati Open when the Argentinean ground out a 3-6, 7-6 (7-1), 6-0 victory over 10th-seeded Czech Tomas Berdych to reach the second round. The 28-year-old, back in Cincinnati after a four-year absence from the US Open warm-up event, powered down 17 aces to rally past Berdych after he surrendered the opening set following a listless start. Berdych found his rhythm early in the match and broke Del Potro for a 3-1 lead and did not lose a point on his powerful serve until the 10th game. But as Del Potro, a semi-finalist at the tournament in 2012 and 2013, worked his way back into the match, Berdych slowly began to lose confidence and failed to win a single game in the deciding set. “During the second set, in the end, I played my best tennis,” 2009 US Open champion Del Potro said. . @delpotrojuan hits 17 aces to beat #Berdych on his return to @CincyTennis for 1st time since 2013. https://t.co/89HI8B7CWG #ATMasters1000 pic.twitter.com/KyS3IaYQA2 — ATP World Tour (@ATPWorldTour) August 15, 2017 <!--//--><![CDATA[// ><!--\n\n\n//--><!]]> “I hit so sure with my forehand. I made good serves and I took all my chances to win. “Mentally, I was strong enough to keep fighting and I think he got down after losing that second set. Then, when I broke his serve early in the third [set], my game started improving and I played much better than him.” Roger Federer stunned in straight sets as Alexander Zverev wins Montreal Masters Del Potro advances to meet American qualifier Mitchell Krueger in the second round. Australian Nick Kyrgios also opened his campaign with a welcome victory as the world number 23 beat Belgian ninth seed David Goffin 6-2, 6-3 in the afternoon heat to reach the second round. Other than in the first game when he had to recover from 40-0 behind, Kyrgios experienced few problems on serve and even secured three breaks against Goffin, who had to take a medical time out for a knee injury during the match. “He obviously wasn’t at 100 per cent today, but you know I’m not at 100 per cent either, so it was a bit of a battle,” said Kyrgios, who has struggled with an array of injuries throughout the season. “But I served well at crucial moments. I’m feeling okay. I think as long as I can keep putting in performances like these and being able to compete I think I’m okay.” Maria Sharapova receives US Open wild card for first grand slam appearance since doping ban In other action, third seed Dominic Thiem of Austria was barely tested in his 6-3, 6-2 second-round win over Italy’s Fabio Fognini, while Jack Sock beat fellow American Tommy Paul 6-3, 6-3 to reach the round of 16. Earlier in the day, big-serving Canadian Milos Raonic announced his withdrawal from the tournament due to a lingering left wrist injury.