There's no doubt that Federer has been slightly on the decline in recent years. It's to be expected for a tennis player who's been playing for over a decade now. Normally, age 30 and beyond is a death sentence, as it's so hard to keep up with the younger generation.
That's not the case with Federer.
The fourth set in particular gave us a glimpse of the player Federer used to be. He showed a ton of emotion and backed it up with his play. He was able to run Murray around the court and hit some impressive winners.
In big matches, he can still find that gear that made him the best player in the world. The only problem is being able to stay in that gear for longer periods of time.
Murray deserves a ton of credit for erasing all of the momentum Federer had built from that fourth set. He got right down to business and took control early.
Looking back, it's not all that surprising. It was clear against Murray that Federer's stamina has diminished. While his physical gifts aren't completely gone, Federer simply can't handle the rigors of a long, demanding match.
Federer's career longevity is a testament to his overall class. Even at 31 years old, he's able to take the No. 3 player in the world to five sets.
It's technically an upset, since Federer was the No. 2 seed. Few should be surprised by the outcome of the semifinals, though.
He's unlikely to be the favorite going into the rest of the Grand Slams this season, but he's certainly a threat for the title, especially at Wimbledon.
You can contrast Federer's career with that of Nadal. While he is one of the best players in the world, Nadal's style doesn't allow him to have the kind of durability that Federer does. His knees simply can't take the constant punishment.
There's no guarantee what kind of player he's going to be upon his return this year.
On the other hand, you always know what you're getting with Federer.
His career may be winding down, but Federer has more than enough in the tank to give tennis fans a couple more years of watching one of the greatest players ever near the top of his game.