Sixth seed Raonic triumphed 6-3, 6-7 (3/7), 4-6, 7-5, 6-3 and goes on to face second seed Andy Murray, the 2013 champion, or 10th-seeded Czech Tomas Berdych It was 25-year-old Raonic’s first win on grass against a top 10 opponent and shattered Federer’s hopes of going on to claim a record eighth All England Club crown and 18th major.
“There was a little opening and I took it,” said Raonic who looked down and out in the fourth set.
“It’s a big impact for Canada. Hopefully, it will be even bigger if I win on Sunday.”
After weathering an early storm, Federer had been in complete control of the semi-final, his 10th at the tournament, until the tie turned suddenly and dramatically in the fourth set.
The 34-year-old, bidding to become the oldest finalist in 42 years, squandered three break points in the set and slipped from 40-0 up on serve in the 12th game.
Federer, whose last Grand Slam crown came at Wimbledon in 2012, had already required five sets to get past Marin Cilic in the quarter-finals, saving three match points in the process.
And the effort took its toll on the 17-time major winner in the decider where he needed treatment on his right thigh and jarred his left knee and foot in a worrying fall. Raonic, nine years his junior, pounced for a 3-1 lead while Federer had to save two more break points in the sixth game.
The Canadian held hs nerve and claimed victory when Federer went wide with a weary forehand which condemned the Swiss star to his first loss in a Wimbledon semi-final. Raonic finished with 23 aces and 75 winners while Federer converted just one of nine break points.
Raonic, playing in his second Wimbledon semi-final after losing to Federer at the same stage two years ago, came out blasting from the start.
He carved out and converted the only break point of the first set for a 3-1 lead before unleashing the fastest serve of the tournament of 144mph (231.7km/h) in the fifth game.
Federer squandered four set points in the 10th game of the second set, the last of which off a sloppy backhand.
But the veteran wasn’t to be denied when Raonic left the door open again in the tiebreaker with his sixth double fault of the tie. The Swiss soon went to another three set points and this time he pounced, levelling the match when a Raonic backhand stab drifted wide.
Federer broke for the first time in the semi-final for a 4-3 lead in the third set as Raonic suffered a sudden loss of momentum, backing it up with a service game to love.
His seventh ace of the contest sealed the set in the 10th game.With his coach John McEnroe commentating for British television, Raonic had to save two break points in the fifth game and another in the ninth of the fourth set.
However, in a remarkable 12th game, Federer was pegged back from 40-0 after serving up back-to-back double faults and Raonic levelled the semi-final on a third set point when the Swiss meekly teed-up an opportunity for the Canadian to pass him.
Federer then required treatment on his right thigh in the changeover.The fatigued legend saved a break point at 1-2 in the decider but only after jarring his left foot and knee in an awkward fall.