The seven-times Wimbledon champion, 32, will have to battle past 23-year-old eighth seed Raonic in the semi-final if he is to remain in with a chance of gaining his record 18th Grand Slam title this year.
Raonic, the first Canadian man in the semi-finals in 106 years, proved his mettle – and his big serve – by dispatching Nick Kyrgios, the 19-year-old conqueror of world number one Rafael Nadal, in the quarter-final on Wednesday.
Many watching saw the performance, which produced 39 aces, 73 winners and just 20 points conceded off serve, as a throwback to the bad old days when grasscourt tennis was a one-shot shoot-out.
"Well, he's got a big serve. Clearly that's what is most visible when you see him play," conceded Federer.
"It keeps him in the match. I've played him in some interesting places like Halle (on grass) where we basically didn't have any rallies whatsoever."
But the Swiss star, who beat countryman Stan Wawrinka in the quarter-final on Wednesday, has a 4-0 career lead over Raonic.
Raonic insists his poor record against Federer will not be a factor when he becomes the first Canadian man since Robert Powell at 1908 to play in a Wimbledon semi-final.
"He's gotten the better of me all four times. But I haven't played him in more than a year and a bit, so I think I'm a different player," he said.
"I've got in close with him in the past and I've found a lot of those things I can sort of pull away that give me a lot of belief that I can do this. I've got to step up and do it.”
Despite his desire to lift what would be a record eighth title, Federer insists he is happy to see a new breed coming through.
"It's just hard breaking through. The points, you fetch them from semis on, not really quarters anymore like it used to be," he said.
"So it's hard I think for a youngster to win or be consistent over three, four, five matches in a row where the big points are."
The semi-final is scheduled for Friday at 1630 Swiss time.