Tennys Sandgren might be behind, but at least he's having fun... it's been a good natured encounter between both players and the court two crowd are enjoying - probably because the sun is also out, at last.

Sandgren faces two break points but the American finds some momentum to win four on the trot and hold, to avoid going a double break behind in the third.

Arvind Parmar
BBC Sport Commentator

Zverev had a bit of pressure there, but handled it well.

Alexander Zverev is taken to deuce but comes through unscathed to hold serve and back up that break a moment ago. Tennys Sandgren is struggling to get a foothold in this match.

Talking of slips... Tennys Sandgren almost goes himself, I'm not sure whether that was because of the surface or Alexander Zverev's bullet-like groundstrokes. The German edges to break point and then fizzes a superb backhand winner beyond Sandgren to take an early advantage in the third set.

There has been lots of debate about the surfaces at SW19 this week, but Wimbledon says its courts are "as good as they have always been" in response to mounting criticism after players continued to suffer falls on Wednesday.

Serena Williams and Adrian Mannarino retired injured on Centre Court following slips on Tuesday, while Australian Nick Kyrgios said the courts were a "joke" and too slow.

Former British number one Tim Henman, a member of the All England Club (AELTC) board, told the BBC: "It's about controlling the controllables."

Henman added: "In terms of the preparation of the surface - the science and the readings - we have all that data. Wimbledon will leave no stone unturned and we hope there will be no more injuries. The courts are as good as they have always been.

"The one thing that has been different this year is the weather. The courts do not get the chance to dry out. Add to that the fact the roof has been closed for the first two days and that is why you will see some slipping and sliding."

Handed my 10-month-old son a plastic bat to try and keep him entertained during that second set - and, you know, plant the seed... - but he looks more McEnroe than Murray at the minute after flinging it across the living room.

Meanwhile, Tennys Sandgren has lost another ball from his pocket during a rally! Unbelievable, he got away with it a few moments ago but loses the point this time. It's not enough to stop the American holding at the beginning of the third set... and the crowd found it entertaining.

Ronald McIntosh
BBC Radio 5 Live commentator at Wimbledon

What a combination!

Serve fired down at 102mph and then a slam dunk put away.

Alexander Zverev is in no mood for messing around today. He storms into a two-set lead in one hour and 10 minutes - didn't lose a point behind his first serve in that one. Impressive.

Tennys Sandgren isn't getting a look.

Everything is going in for Alexander Zverev at the moment! He awkwardly frames one but it lands in and foxes Tennys Sandgren, who lashes into the net with an overhead from the baseline.

Zverev takes the double break and is cruising towards a two-set lead.

Harriet Dart and Heather Watson are serving for the match on court four...

Alexander Zverev rattles through a hold to back up that break a few moments ago and will need to change his racquet before heading to the receiving to face the Tennys Sandgren serve with new balls coming at him - his big-hitting approach is putting those strings under some serious strain.

That's unusual! Tennys Sandgren is halfway through a rally with Alexander Zverev when a spare ball slips out of his pocket, the umpire calls a let and the point will be replayed...

Zverev is really looking in the mood here, though, Sandgren cuts one short but the fourth seed is up to it in a flash and slices a superb forehand across the tape to bring up two break points.

The German fails to convert either but will get a third chance. Sandgren thinks he's cancelled it out with an ace, but Zverev challenges and Hawk Eye shows it's wide. And Zverev then does break!

Barbora Krejcikova is playing in her second main draw match at Wimbledon right now. She is in the driving seat against Germany's Andrea Petkovic, looking to back up her run to the French open title

British duo Luke Johnson and Anton Matusevich have just lost a first-set tie-break 7-3 to Australian pairing Alex de Minaur and Matt Reid on court 10.

No such trouble for Harriet Dart and Heather Watson, who are absolutely flying at 6-3 4-1 up on court four against Kaia Kanepi and Shuai Zhang.