Raonic gets the better of Federer as they go toe to toe (or should it be racquet to racquet?) at the nets. 

Milos Raonic takes a swing at a Roger Federer serve and wiffs only thin south London air.

Either Federer has added a googly serve to his repertoire or Centre Court is getting a little bobbly - like a favourite jumper - through nearly two weeks of heavy-duty use. 

Ian Bradley: This Federer Raonic match feels like the baton being passed on to the next generation.

David Robinson: Raonic is moving around the court extremely well. This could be tough for Federer.

Sarah Willey: Please can you tell me why Raonic always bounces the ball EXACTLY 8 times????

John McEnroe
Three-time Wimbledon singles champion on BBC TV

Milos Raonic has really brought his 'A' game and has taken it to Roger Federer.

Milos' serving is huge, but he has done lots of other things well, including moving well. He is covering the court and that is getting to Federer.

Milos is a student of the game and that's starting to pay off. Federer has got to shake off whatever tightness he has physically and mentally.

A none-too-clever slice into the tramlines from Milos Raonic allows Federer back to 40-30. The Canadian had a bit of prime Centre Court real estate there as well as having an easy bounce and options for a winner.

If he gives away a few free points, Raonic also comes to collect them.

A rocket tee-off skids off the service line and Federer frames into the cheap seats to fold out of the game.

He may have lost that first set but there have been glimpses of that Federer magic. 

Milos Raonic shows that he has a whole arsenal to back up that bazooka of a serve.

A backhand paddled down the line catches Federer by surprise as he targets what he thought was the Canadian's weaker wing.

That is 30-15 and Raonic is not far wide with a poke down the line as he runs down a Federer drop-shot with a startling turn of pace.

Still, Federer is first on the board in the second and that is all that the scoreline shows.

Eleanor Oldroyd
Presenter, on BBC Radio 5 live

We know Roger Federer can do it, he knows he can do it but the last thing he will want, at the age of 34, is another three-hour epic.

Milos Raonic takes the first couple of points as he comes to the net and eagerly bangs away volleys.

Is that a hint of nerves? A double fault for 30-30.

Better from Raonic as he comes in to the net to punish a stretching Federer.

Oh, a bit of magic from Federer as he dusts away a lovely cross-court pass.

Deuce time.

But the Canadian is not to be denied. Federer cannot mine up any more diamonds. First blood to the underdog.

Image source, Reuters

Andy Mitchelmore: Any idea why Raonic is wearing a mouthguard/retainer? Is that not distracting?!  

It's to help with his bad back. Seriously, read it here., external

Theo Bowyer: Raonic's serving looks ominous... The Fed Express is stalling at the moment   

Annabel Croft
Former British number one on Radio 5 live

Raonic has a sensational serve, it's such a simple motion, using that height and great racquet-head speed. His average second serve speed is almost the same as Federer and Murray's average first-serve speed. 

Image source, Getty Images

John McEnroe
Three-time Wimbledon singles champion on BBC TV

We noticed when Milos played against Sam Querrey (in the quarter-finals) he had settled into a groove and took it to Querrey.

But his serve statistics in terms of miles per hour were off, maybe by up to 10mph. He knows he has to bring everything he has got against this guy - and is bringing it all today.

Stefan Edberg brought a bit of serve-volley to the Federer game a couple of years back, but it looks a little rusty as the Swiss revives the tactic and plants a stretching volley long.

That is the only point he loses in the game though.

Now the main event, Raonic to serve for the opener.

Here is the moment Raonic broke Federer early in this set. Is Federer still feeling the affects from that marathon quarter-final?

Milos Raonic's forehand slips his grasp, floating long on a couple of occasions to put him 0-30 down. 

A little rumble around Centre Court as Federer's fans lean in in anticipation.

The rest of the game is soundtracked by thudding serves and a collective sucking in of cheeks.

A barrage of enormous serves - the biggest clocking in at 143mph - whisks away the game.

In cricket this would be referred to the third umpire. Was this a cool catch from the ball boy or did he spill it? You decide. 

Roger Federer runs in and gleefully swats away a running volley to seal the game.

Holding serve is not the challenge now though.

He has to break Milos Raonic in one of the Canadian's next two service games to keep this opening set alive.

That is a tall task.