Over on Court One, there could be a shock brewing...

Sam Smith
Former British number one at Wimbledon

Karolina Pliskova will be mightly relieved and who thought we would say that? That was one of the finest debuts from a British woman at Wimbledon by Harriet Dart.

This should be a springboard now. She can start playing some of the bigger events I'd love to see her back in 12 months without needing a wildcard. This is a young woman who has a bright future and will be back here in her own right.

Image source, Reuters

Ace number five for Federer takes him to 30-0.

Oh, that's a whip and a half from the top seed, nailing a forehand down the line. He clonks down another ace, this time on his second serve, to move within a game of the second set.

Boris Becker
Three-time Wimbledon champion on BBC TV

Lajovic needs to go back to basics, this is a game he knows how to play. I don’t see him moving comfortably. Movement is an underrated quality on the grass. You slide away and have to consistently move your feet to be in the right positions. I don’t find Lajovic doing that.

The Serb draws two errors out of Federer, and holds to warm applause from the Centre Court crowd.

Break point to Federer, courtesy of a backhand that whizzes past Lajovic.

Oh, and the Serb finds a stonking winner of his own to close that advantage down!

40-40.

Roger Federer somehow manages to make a forehand cross-court and Lajovic, surprised, lashes the ball over the baseline.

Every time Lajovic edges in front, Federer finds a return to peg him back. The Swiss launches a backhand out and Lajovic is within a point of taking the game, but he double faults at the crucial moment.

Deuce.

Sonia Oxley
BBC Sport at Wimbledon

There’s a big queue outside court 12 of people hoping to witness Harriet Dart pull off an unlikely upset.

Fair to say the ladies loo queue next door is moving a lot faster...no-one wants to give up their seats on court in a hurry.

Harriet Dart squats low to punch a backhand deep towards the baseline. Karolina Pliskova then wraps a groundstroke into the tape. She's not quite out of this yet... 15-30.

Saj Chowdhury
BBC Sport at Wimbledon

"Harriet!" Somebody shrieks.

Never heard that name shouted so loud.

Now somebody shouts "strong game"

Does she have the Eye of the Tiger. She knows Wimbledon like the back of her hand. Or is that backhand?

Sadly she's one game from defeat against Pliskova.

BBC One

Double tennis action on your tellies now.

We're live on BBC One and BBC Two - and there's a whole heap of outside court streams to take your pick from.

Harriet Dart saves the first as Pliskova goes wide, but there's a screech of frustration from the Brit as she slings a backhand into the tramlines.

Pliskova will serve for the match.

Backhand meets backhand, before Dusan Lajovic ups the pace and cracks a forehand winner beyond Roger Federer for 15-15.

Federer eases his way back into the game, though, racing to 40-15, before Lajovic guides a backhand long.

Image source, Getty Images

Nice, wide serve from Harriet Dart, before she wrong-foots Pliskova by slapping a follow up down the centre.

But then a sloppy miscue, popping a backhand long from the net. Another backhand drifts long and that's two break points for Pliskova.

Meanwhile on Court One fourth seed Sloane Stephens is battling to maintain her place in Wimbledon.

The US Open champion has lost the first set to Croatia's Donna Vekic but leads early on in the second set.

You can watch that match here.

Boris Becker
Three-time Wimbledon champion on BBC TV

Federer is almost 37 years young, if you can get an easy match under your belt without exerting too much energy it is a bonus. But I’m sure Lajovic has different plans.

That's nice from Dusan Lajovic, meeting a cross-court whip from Federer with a strike of his own that finds the corner of the court.

Federer gets on the board at 30-15, but a rare shank from the Swiss allows the Serb to hold.

Lajovic is on the board!

Karolina Pliskova just turning the screw a little bit, fending off the challenge of the world number 171.

The Czech seventh seed races to 40-15, but Dart's not done yet. The wildcard, on her Wimbledon debut, goes deep and forces Pliskova into the net.

She can't wrap a racquet around the next punchy serve though. Pliskova holds.

Boris Becker
Three-time Wimbledon champion on BBC TV

This seems to me like a practice match.