French Open champion Alexander Zverev came through a testing four-set battle with Belgian debutant Alexander Blockx to reach the Wimbledon second round on Tuesday. The German, who was beaten in round one last year, won 6-4, 6-7 (8/10), 7-6 (7/5), 7-6 (7/0) on Centre Court and will next face France's Valentin Royer. Zverev was in danger of becoming the first reigning men's Roland Garros champion to go out in the first round at the All England Club since Rafael Nadal in 2013 at several points in the match.