Tim Henman
Former British number one on BBC One

When you look at Alexander Zverev's serving, it is absolutely immense. It looks like he could serve all day and all night like this because it takes so little out of him.

He is more aggressive from the back of the shot and cool when he gets the chance to step in. He is going to be tough to play against if he keeps this level up.

American Ben Shelton has become the highest seed to exit Wimbledon so far following a five-set defeat by Finland's Otto Vertanen.

World number 140 Virtanen won 6-4 3-6 6-7 (8-10) 6-2 7-6 (11-9) against the fourth seed in a match lasting four hours and 21 minutes.

The prize for Virtanen is a second-round tie with Britain's Arthur Fery.

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The back and forth meeting between Thanasi Kokkinakis and Alexander Bublik has gone to a fifth set after Bublik, the 10th seed, took the fourth 6-3.

Kokkinakis has opened the decider with a hold to 15.

Lois Boisson secures the hold with an ace on advantage. She came up with a couple of big first serves in that game.

It remains on serve in the third set.

Lois Boisson's second serve on the second break point was so slow but Elena Rybakina makes a hash of her backhand return.

Alexander Zverev is serving very well so far in this second set and Alexander Blockx can't get a look in as the German second seed holds to love.

Errors now from Lois Boisson. Two break points for Elena Rybakina.

'Let's go Billy, let's go' rings around Court 18 as Billy Harris holds against Karen Khachanov.

Set three has not gone to plan so far for the Brit, as he finds himself a break down, but there is no reason why he can't fight back - especially with the SW19 crowd behind him.

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Harry Poole
BBC Sport at Wimbledon

My Brit-watch tour today continues where it began, back on court three.

Katie Boulter lost the first match of the day in this arena to Italy’s 18-year-old qualifier Tyra Caterina Grant, as Tuesday began with another home loss.

But things have begun to look much more positive since then, with excellent wins for Katie Swan, Arthur Fery and Jacob Fearnley.

Now, Toby Samuel is attempting to pull off one of the upsets of the day against Czech 15th seed Jakub Mensik.

Samuel enters Wimbledon in great form, having reached the Eastbourne semi-finals last week despite having never previously won a tour-level match.

Czech 20-year-old Mensik is one of the most exciting young players in the men’s game, and has turned this around since losing the opening set.

But Samuel raises a celebratory fist to the crowd as he strikes first in set four… Game on!

A few chuckles on Centre Court as a fan shouts "come on Alexander" which catches the attention of both players...

On court, Alexander Blockx serves his way to another hold.

Elena Rybakina has come through a tricky game to hold. The third set remains on serve.

Elena Rybakina saves the first break point with a big first serve. Lois Boisson's cross-court forehand fades into the tramlines on the second.

Oh hello!

Toby Samuel breaks Jakub Mensik at the first time of asking to push ahead in set four.

Samuel found himself 15-40 up, similarly to a game at the beginning of the third set, which he failed to take advantage of. This time round, Samuel steps up and the crowd roars when Mensik's shot goes long.

Is the comeback on?

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It's a confident start to the second set from both players as Alexander Zverev holds.

Zverev showed two strengths to his game there with a delicate half-volley at the net and a passing backhand down the line which left Alexander Blockx stranded.

The first break points of the deciding set on court one go to Lois Boisson as Elena Rybakina slams a backhand into the net. 15-40.

A comfortable hold to start the second set for Alexander Blockx.

It'll be interesting to see how the Wimbledon debutant and world number 36 responds, having given up his previous service game - and therefore the set - in such a tame manner.

As Tim Henman says, Alexander Zverev is one of the most consistent servers in the men's game and Alexander Blockx has only one chance to challenge it if the Belgian is going to stay in the first set.

Blockx wins the first point but Zverev steps it up from there and wraps up the set in 30 minutes.

The German made 81% of first serves, won 81% of first-serve points and 80% on his second serves.

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Tim Henman
Former British number one on BBC One

That really was a dreadful service game from Alexander Blockx.

Before that, he looked really comfortable on serve. His percentage was very high and he was giving Alexander Zverev very few opportunities.

But when we reflect on the serve quality of Zverev - across speed, spin, depth and width - he is at 9.5 out of 10 which is absolutely phenomenal. When you're coming out to serve for the set, that's absolutely the form you want to be in.

Lois Boisson comes through a challenging hold to 30 to level the set at 1-1.

In the next game, a deep forehand isn't returned by Elena Rybakina, who then double faults for 0-30.

The second seed recovers to 30-all with a forehand winner on the approach and an ace down the T and closes out the hold with another forehand winner into an open court off a wide serve.