Seven-time champion Federer came from a set down to overcome Swiss compatriot Stanislas Wawrinka 3-6 7-6 (7-5) 6-4 6-4 on centre court at the All England Club.
The match marked the first time that Federer has dropped a set in this year's championships, with his performance a marked improvement on 2013.
Federer was beaten by the unheralded Sergiy Stakhovsky in the second round last year, but the 32-year-old appears to have an excellent chance of regaining a title he last won in 2012.
And while Federer refused to look beyond his last-four clash with either Nick Kyrgios or Milos Raonic, the 17-time grand-slam winner is understandably pleased with his serene progress through the draw.
"Stan played great - especially for the first two sets," Federer said. "I think after that he started to get tired. But he was hitting the ball too well, too cleanly for me to do anything.
"It's difficult when you know someone so well. We know our patterns really well. I wish him the very best for the season because clearly already he's had a beauty.
"I don't want to get too far ahead of myself; I am just glad I am back strong after the disappointment of last year.
"I left really deflated last year so it's great to be back in the semi-finals and having the chance to go one or two steps further."