Wawrinka shocked by Medvedev, Murray and Nadal through to second round at Wimbledon

Russia's Daniil Medvedev celebrates winning the third set during his first round match against Switzerland's Stan Wawrinka in the Wimbledon Championships in London, Britain on July 3, 2017. [Photo/Agencies]

"I'm really happy," he said. "Wimbledon is my favourite Grand Slam. It was in my juniors and still is.

"One year ago I was 250th in the rankings and if someone said I would not only play on Centre but win I would say: 'You are joking!'"

Wawrinka has only reached two quarterfinals in his 13 appearances at Wimbledon.

"I wasn't feeling the way I wanted to feel but I played against a great player," said Wawrinka. "I had problems with the knee since Queen's. It is not something new but something I had in the past. Apparently grass is not the best surface for my knee and I need to figure out what I'm going to do and come back when I have no pain."