Before the Australian Open I really did feel that the demands of fatherhood, plus the trouble that he showed at times closing out big matches last year, meant that we had seen the best of him.
I still thought he would have occasional great moments, but that they would become fewer and fewer.
Yet that one performance against Andy Murray at the final in Melbourne blows that theory out of the water.
Federer's decline will happen one day - it might be next year, it might be the year after.
But there's one thing you can say for sure about this season: he has got it back.
His form ebbed and flowed a little through the tournament - just as it did last year - and he even looked a little shaky in the opener against Igor Andreev, but when it came down to the big points in the big matches he came through, and in style.
Never was it better illustrated than in the third set of the final against Murray. With the Scot serving for the set, Federer came up with the goods to break, then closed out the win.
Not for a second did I think I'd be saying this, but if Federer wins again at Roland Garros then the Grand Slam is genuinely on.
I spoke to Andy after the final, and the thing that really got to him about his loss wasn't the missed set points in the tie-break, it was faltering when serving for the third set.
His star is still rising, though, and there's no reason to think that he won't spend most of this season as the number two in the world.
Part of that, sadly, is to do with Rafael Nadal's injury trouble.
He obviously thought he had the problems licked, and while nobody knows - not even him - how bad the latest set-back will be, it seems like the trouble isn't going away yet.
Let's all hope he'll get back to full fitness, because he's a cracking bloke and his talent is fantastic. I thought the best two sets of the whole tournament were the stunning first two against Murray in the quarter-final.
Of the other players, I was pleased to see Marin Cilic - one of my pre-season tips - play so well, particularly when he dug in and saved the match against Bernard Tomic.
Novak Djokovic had his moments too, and I believe he will stay in the world's top three and win more Grand Slams in the coming years. I still do think that Murray is a better player, though, and he will probably spend most of his career ranked above the Serbian.
---It feels like the women's tournament in Melbourne has ushered in a new and incredibly exciting period for women's tennis.
Serena Williams was simply magnificent. It's clear that she wasn't fully fit at any stage of the fortnight, but the way she played through the pain - and the way she performed in the final - was just amazing.
After everything that surrounded Kim Clijsters's comeback last year, it's easy to forget that Justine Henin's return was in its way every bit as impressive.
Perhaps more so, in fact, because while Clijsters relies on power for much of her success Henin relies on touch and skill, and getting that back to Grand Slam level so quickly is astonishing.
Either way, it's going to be the most exciting season in women's tennis for years.
Clijsters's mysterious collapse as she went out of the tournament was bizarre, but clearly just a blip. Her win at the US Open last year tells you everything you need to know about her.
Elena Dementieva is also looking good so far in 2010 - her match against Henin was the best of the women's tournament - and from what I've heard it sounds like Jelena Jankovic could be on the way back to her best.
You can also throw Dinara Safina into that mix; I feel she'll have a much better season now that she won't have to deal with people questioning her number one ranking everywhere she goes!
But while those players and Serena could enjoy another great year, I don't think that Venus Williams will be much of a threat - with the sole exception of Wimbledon, where she will always challenge.
- Roger Federer
- Andy Murray