Federer: Warming up is not the most fun bit...

The Swiss veteran is in the hunt for his 21st Grand Slam title at Wimbledon and cruised through to the quarter-finals courtesy of a straight-sets win over Matteo Berrettini on Monday.

However, Federer has revealed that he goes through a meticulous preparation routine before every match, which is far more elaborate than the one he used to employ as a youngster.

"I think I have to warm up much more than I used to which is not the most fun bit, to be honest," Federer, who will play Kei Nishikori in his 55th Grand Slam quarter-final, told reporters.

"I used to jump up and down for a minute when I was 21 or 19. Now we go through this entire routine. I'm like, 'Really, do we really have to do it?'

"I guess it helps, so I'm doing it. When I get bored of it, I'll stop playing tennis completely or I'll stop that routine first before I stop playing."

Federer also revealed that Berrettini's coach had some interesting words for him after his 6-1, 6-2, 6-2 win over the Italian.

"His coach congratulated me and thanked me almost," Federer said.

"I was like, 'Why?' He was like, 'It's good for him to get a lesson. You guys are a bit tough, but I get it.'

"It's important he's not too disappointed because he's had a great run. I lost sometimes the hard way."