LONDON: Roger Federer says the key to winning majors is making sure his average is as high as possible - every round.

There is nothing average about Federer, though, as he proved again on Wednesday by turning his 100th Wimbledon match into an exhibition of his magic, outclassing Milos Raonic 6-4 6-2 7-6(4) to reach the semi-finals for a record 12th time.

The Swiss maestro, 36 next month, played his best tennis of the tournament to dismantle the big-serving Canadian - avenging last year's semi-final defeat in stunning fashion.

With defending champion Andy Murray losing earlier on Centre Court to Sam Querrey and Novak Djokovic retiring with an injury against Tomas Berdych, Federer is now overwhelming favourite to become the first man to win the title eight times.

"I can't believe it's 100 matches, it's a lot but I'm very happy my body has kept me going all these years," said Federer who will face Berdych in Friday's semi-finals.

"You have to make sure you average is as high as possible every day and I think I'm doing a great job this week."

Raonic might have had the 140 mph serve in his locker, but Federer owns a magic wand that he used to make the world's sixth best player look like a lumbering also-ran.

It was hard not feel sorry for Raonic at times.

Usually when a player is taking the kind of beating Federer was handing out on a sunlit Centre Court, the crowd throw their weight behind the underdog.

That rule does not apply when it is Federer, king of Wimbledon, inflicting the punishment in the silky manner only the 18-times grand slam champion is capable of.

When, to his immense credit, Raonic finally began to threaten in the third set, going 3-0 up in the tiebreak, it was Federer they were cheering for.

When he responded with two majestic forehands, one apparently defying physics as it curled around the net post, they were in raptures in the stands and former great Rod Laver smiled in admiration from the Royal Box.

"I was sort of moving on, let's see if he can do it again. He kept doing it," Raonic told reporters. "He kept a very high gear the whole entire time without giving many real glimpses.

"I think that was the most defeating thing."

There was a slightly subdued atmosphere on Centre Court after home favourite Murray had hobbled to defeat against Querrey. But once the old place filled up and Federer hit his stride the British player's defeat was forgotten.

Federer struck two rasping backhand winners in the fifth game and raced across the turf to punish Raonic for failing to put away a volley, pummelling a forehand straight through the ducking Canadian to seize a decisive break.

Raonic's belief ebbed away at the start of the second set when a careless forehand gifted Federer another break and the third seed went for the jugular, grabbing another break of serve as he sauntered into a two-set lead.

Federer was made to sweat a little in the third set, saving four break points at 3-4 as Raonic finally began to hit his groundstrokes with menace.

When Raonic opened up an early lead in the tiebreak it looked as though Federer might drop his first set of the tournament, but he responded in style to win seven of the next eight points and earn himself a standing ovation.