Zverev shakes off pain during Hamburg win

Alexander Zverev enjoyed a comfortable first-round win at the Hamburg Open Wednesday but conceded that he continues to manage pain in his left knee resulting from a nasty fall at Wimbledon.

The World No. 4, who overextended his knee during a slip and fall in a third-round win over Cameron Norrie at the grass-court major, dropped just seven points on his first serve and did not face a break point in a 6-2, 6-2 win over Jesper de Jong.

"I was still unsure this morning if I was going to play or not and during the warm-up I was in quite a lot of pain," said Zverev, who has a bone edema and tear in the capsule of his knee. "But somehow when I step on this court it disappears a little bit when the adrenaline gets going.

"I have an injury where I know where I stand and it will take time to heal. It won't heal in the next few days, it will take weeks and it's up to me if I am going to play like that or not."

Making a successful transition from his fourth-round run at Wimbledon to the clay on home soil in Germany, the defending champion collected his 41st match win of the season and improved to 12-1 in first-round outings this season.

Fourth seed Francisco Cerundolo and seventh seed Luciano Darderi reached the quarter-finals Wednesday. The Argentine Cerundolo raced past wild card Maximilian Marterer 6-0, 6-2 while Darderi overcame Alexander Shevchenko 6-3, 2-6, 6-3. Spaniard Pedro Martinez is also into the last eight following his 6-4, 0-6, 7-5 victory against Ugo Blanchet.