Jannik Sinner mishits a forehand and one Dimitrov ace later, he's staring at a 30-0 deficit.

But a long forehand from the Bulgarian and a fortunate Sinner net cord - one apiece on that score - later, it's 30-30.

However, Sinner sends a second-serve return long - the latest in a number of unforced errors - to bring up set point, only for a Dimitrov backhand to find the net. Deuce. Wow, what a rollercoaster set this has been.

Greg Rusedski
Former British number one on BBC Radio 5 Live and BBC Sounds

Wow. Wow. Wow. What a way to break!

There was nothing Jannik Sinner could do with that return because it was on the back of the baseline. We saw everything in that point, a drop volley that clips the net and a short short that made him slide forward.

At the moment, Grigor Dimitrov is winning all the big points at the moment. Can he serve it out? If he does, this is going to be a long way back.

Image source, PA Media

The world number one must be wondering what's hit him.

A booming serve is returned with interest and Jannik Sinner cannot adjust his body quick enough as it's right at his feet.

For the second time, Grigor Dimitrov will serve for a two-set cushion.

Grigor Dimitrov takes another tumble... but he won't care as he lunges to make a half-volley at the net that clips the top of the tape and drops over the other side much to Jannik Sinner's disappointment.

A chipped. drop-shot-esque Dimitrov return later and he has three break points!

Image source, Getty Images

Jess Anderson
BBC Sport at Wimbledon

Hello. Whatever was done in that medical time out appears to have the desired effect.

It's not often you see much celebration from Jannik Sinner. More of a focussed, get on with it kind of guy. But he roars towards his box and raises a fist to the crowd as he breaks back to put himself back on level terms in set two.

Could be huge.

A roar of delight - and relief - from the Italian.

Grigor Dimitrov slips for the second time in the game and Jannik Sinner pounces, sending him this way and that before finally finding a forehand winner.

Image source, PA Media

Not much anyone - even the world number one - can do when Grigor Dimitrov crushes an ace into the corner of the service box.

After a slip costs him next point, Dimitrov rains down another massive missile of a serve - 30-15 - but a fine Sinner return restores parity.

And a Dimitrov forehand goes long! Break point....

Greg Rusedski
Former British number one on BBC Radio 5 Live and BBC Sounds

There is no hesitation from Grigor Dimitrov.

Anything that is short, he is taking on. His game plan is crystal clear. He knows exactly what he has to do.

If he continues to execute in this manner and he can close out this second set, he becomes the favourite to upset the world number one.

That medical time-out has helped Jannik Sinner's service game, if nothing else.

Seems nothing wrong with that elbow as he slams down a couple of big hits on the way to a hold - and ensuring Grigor Dimitrov must serve out for a two-set lead.

Image source, Getty Images

This is very quickly getting away from Clara Tauson.

Iga Swiatek races into a 15-40 lead to earn two break points and the Pole takes her first opportunity - stepping into Tauson's second serve and crashing a backhand winner down the line.

Andrew Cotter
Commentator on BBC TV

Sinner is not quite himself, but he is a happier man now than he was.

For Dimitrov, he is still in the prime position to reach the quarter-finals for the first time since 2014 when he beat Andy Murray. Andy Murray, at seed five, is the highest seed he has ever beaten in this tournament.

Grigor Dimitrov uses all of the court to place a pretty routine volley right on the line to the oohs and aahs of Centre Court.

Jannik Sinner is barely getting a look in on the 19th seed's serve. He must now serve to stay in this second set.

Iga Swiatek has really turned it on in this second set.

She's racing towards the quarter-finals. A hold to 15, sealed with a pair of aces and 23rd seed Clara Tauson faces an uphill battle from here.

Image source, Getty Images

Gary Rose
BBC Sport at Wimbledon

Iga Swiatek looked frustrated after an incredibly close line call for out at break point, but she puts that behind her to come out on top of a rally that pulled both players all over the court.

A crucial advantage for Swiatek now as she looks to wrap up reaching the quarter-final of a Grand Slam for the fourth time in a row.

Greg Rusedski
Former British number one on BBC Radio 5 Live and BBC Sounds

In the opening game, Sinner took a slide on both feet on the far side of the court and he hit his elbow. But we didn't think anything of it because he has played a set and a bit.

Maybe that explains why his serve isn't firing how he would like today. He looks like he is in a little bit of pain.

Let's hope this isn't anything too serious and he can take some anti-inflammatories and get back to business.

Image source, Getty Images

An unreachable Dimitrov ace down the T won't aid Jannik Sinner's recuperation.

The Bulgarian's combo of power serving and slice approaches is posing a quandary Sinner cannot answer.

A slice that keeps particularly low makes the world number one looks a tad foolish as he misses it completely and Dimitrov has his latest hold to love.

However, Sinner responds in kind with an equally impressive service game.

Getting that first serve in is so important for Clara Tauson because, the moment she doesn't, Iga Swiatek is jumping all over the second serve.

The Polish eighth seed does so to brilliant effect, whipping a forehand cross-court to bring up three break points.

Tauson manages to save the first two and should do the same with the third but can't finish it off.

Superb defence from Swiatek and then a thumping cross-court backhand winner to break.

Image source, Getty Images

Andrew Cotter
Commentator on BBC TV

It was the fall which caused pain to Sinner's elbow. It doesn't look too bad when we watch it on the replay.

He is bracing himself and gesturing to the physio who seems to be rubbing some friction on it. He pops a painkiller and all should be well.

Listening in to Sinner's conversation with the trainer, he said he's been feeling his elbow crack whenever hitting the ball hard after a first-set fall.

The physio is massaging the joint but Sinner looks in a decent amount of discomfort. That'll not be helped by the scoreline of course.