Carlos Alcaraz holds to put us back on serve in this third set.

Huge celebration from Katie Boulter as she fights back from 5-2 down to win the first set!

Another tense rally on this fourth set point before Solana Sierra's backhand goes low into the net.

The Brit is halfway to the third round.

Another set point comes and goes for Katie Boulter as she thwacks a backhand into the net.

But a big serve down the middle sets up a fourth set point...

Image source, Reuters

Andrey Rublev, the 14th seed, has come from behind to win against South African Lloyd Harris 6-7 (1-7) 6-4 7-6 (7-5) 6-3.

Karen Khachanov has beaten Shintaro Mochizuki from Japan 1-6 7-6 (9-7) 4-6 6-3 6-4 to book his spot in the third round.

Good stuff from Ollie Tarvett.

He gets his nose in front again, holding to 15.

Brilliant from Solana Sierra.

She whips a forehand winner after staying in the longest rally of the match so far.

Katie Boulter may still be ruing the double fault that saw her throw away the first of those two set points.

Katie Boulter is on the brink of taking this first set after a favourable bounce off the net chord to take Solana Sierra's forehand wide.

Portuguese Nuno Borges speaks after being Briton Billy Harris to reach the third round: "It was three sets but this one felt like more. I'm pleased to get through and in the end I think I played a very good match."

On the crowd: "The crowd was very pleasant, not hostile at all. I can tell you I have had much worse so I'm very grateful! I can enjoy the atmosphere even though it is not for me. I'm just trying to enjoy the moment and that's what I will do in the next round."

Simple as you like for two-time Wimbledon winner Carlos Alcaraz.

He wraps up his service game with a backhand volley after serving wide.

Blistering forehand from Solana Sierra and that's one of those mini breaks back. That was clocked at 96mph.

Katie Boulter keeps her cool, though, and a serve into the body helps her keep the upper hand.

Image source, Getty Images

Belgium's Elise Mertens, who is 24th seed, lost a tie-break against Ann Li in the first set, but is a break up in the second.

Linda Noskova has taken the first set 6-2 against Eva Lys and leads the second.

American and 13th seed Amanda Anisimova has taken the first set 6-4 against Renata Zarazua.

Perfect start for Katie Boulter as she earns the mini break at the first time of asking, a slice into the net hands it straight back but when Solana Sierra twice dumps the ball into the net, the Brit has a good advantage in this tie-break.

Gary Rose
BBC Sport at Wimbledon

The seats around Court One are filling up nicely and the crowd is ramping up the support for Katie Boulter.

It felt like the support from the stands energised Cameron Norrie on this court a little earlier, helping him to beat Frances Tiafoe, and they are doing their bit for Boulter now.

Spirited stuff from Ollie Tarvet.

The Brit saves two break points to stay in touch with Carlos Alcaraz, and after three deuces, manages to secure an impressive hold.

He needed that.

A sixth double fault of the set for Katie Boulter but it comes at 40-0.

She completes a comfortable hold when Solana Sierra finds the net next point.

The first set will be decided by a tie-break...

Big smile from Solana Sierra after she brings Katie Boulter to the net with a drop shot and then nails a backhand past her down the line.

Good hold for the world number 101 from 15-30.

Billy Harris floats a backhand across the path of Nuno Borges.

The crowd, Harris and Borges think it's in and the third set is done but they are all wrong!

Borges' backhand down the line is so accurate and Harris can only hit into the net.

He hits his cap with the racquet as his frustration is clear to see with two set points disappearing.

Billy Harris fires an ace down the centre which leaves Nuno Borges stranded.

However he hits into the net on the next point thanks to a poor backhand.

An unforced error from Borges brings up two set points for Harris.

Trouble is brewing for Katie Boulter at 15-30 but the Brit responds.

A gutsy second serve at 30-30 sees Solana Sierra hit a backhand into the net and when the Argentine goes long on the next point, it's three games in a row for Boulter.