Defending champion Novak Djokovic cruised through to the third round of Wimbledon while Reilly Opelka caused the big shock of the day by knocking out Stan Wawrinka.

Big is the operative word given, at a shade over 6ft 11in, Opelka is the tallest man ever to have an ATP ranking.

The 21-year-old American, who claimed the junior title at the All England Club in 2015, had only won one grand slam match before this tournament but recovered from two sets to one down to defeat 22nd seed Wawrinka 7-5 3-6 4-6 6-4 8-6.

"It's a huge win," said Opelka, who next faces a fellow big server in former finalist Milos Raonic.

"More so the situation of the match, being down two sets to one against him. Break points the first game in the fourth set, and that's tough, obviously. He easily could have walked away with that in four sets. But I'm just proud of how I competed and how I handled the big moments of the match."

Ivo Karlovic looked like he might make it a double for the giants but the Croatian lost out in five sets to 5ft 8in Thomas Fabbiano.

Djokovic won the first five games and did not look back in a 6-3 6-2 6-2 victory over American Denis Kudla to set up a rematch with Pole Hubert Hurkacz, who he beat comfortably in the first round of the French Open.

Fourth seed Kevin Anderson, the man Djokovic conquered in the final last year, dropped a set against Janko Tipsarevic but recovered to win 6-4 6-7 (5) 6-1 6-4.

Anderson is playing only his fifth tournament of the season because of elbow problems, and he said: "It's definitely getting better. I think it's a process. But, having played four sets today and feeling really good and a match a few days ago, that's a very positive sign for me.

"I thought I served well throughout, not getting broken. Of course I'm really pleased with how my body held up. That's the most important thing right now for me."

The youngest man in the draw continued to hit new heights, with 19th seed Felix Auger-Aliassime reaching the third round of a slam for the first time.

The 18-year-old Canadian, who could play Djokovic in the fourth round, defeated another young gun in France's Corentin Moutet 6-3 4-6 6-4 6-2.

Auger-Aliassime admitted he had to battle his nerves, saying: "There's a bit of a pressure. I think it's quite funny, because I think for a lot of players when they play their first grand slam, they have zero expectations.

"A player like Moutet today, he's loose, nothing to lose. For me to play, not my first slam, but to win my first match and already people are talking about me going far, it's something very odd."

Tenth seed Karen Khachanov faced a potential banana skin in Queen's Club champion Feliciano Lopez but hit back after losing the first set to win 4-6 6-4 7-5 6-4.

Daniil Medvedev, the Russian 11th seed, matched his best run at Wimbledon by beating Australian Alexei Popyrin 6-7 (6) 6-1 6-4 6-4 and next plays 21st seed David Goffin, who defeated Jeremy Chardy in straight sets.