Ooof. Slow second serve from Tiafoe but Norrie returns it long. Deuce.

Backhand winner from Norrie. He does have a set-point! 30-40.

Marie Bouzkova is going nowhere. She arrows a backhand into the corner to move 2-1 ahead in the breaker...

Can you believe it? Cam Norrie can sense set-point, but he gets too much on a drop-shot volley and Tiafoe reaches it, before dispatching a passing winner.

30-30.

Jess Anderson
BBC Sport at Wimbledon

Sabalenka is getting increasingly vocal out here on Centre Court.

A huge roar as she sends us to a tie-break.

Aryna Sabalenka breaks straight back to force a tie-break - a brilliant response from the top seed!

She earns her first break point of the match at a crucial time - but drags the backhand wide when she looked to be in control of the point!

There's a big shout when she brings up another, though - half in celebration, half frustration it seems - and an even bigger cry when she leaves Marie Bouzkova rooted to the spot with a powerful backhand winner.

Tie-break time...

Right then, the business end, crunch time.

Tiafoe gets a serve all wrong to slip to 15-30.

And then Norrie wins the next two points to hold! From 0-40 down.

Court One is loving this.

Sonay Kartal on her victory: "Yeah obviously I knew that match was going to be tough. I knew I'd have to go out and win it. I felt good on court today. I was hitting it really clean. It was one of those good days at the office."

On matching last year's run to the third round: "I wanted to back that up this year. This tournament I wanted to show I'm at this level and can consistently play here."

On her progression over the last year: "Last 12 months I have thrown myself on to the scene. This year I've taken a conscious effort of only wanting to play the bigger matches against the best players on tour, day in, day out. I'm playing with more freedom and more confidence."

Oh my, it's the same shot again! Certain winner somehow returned, but just long. That's three breaks saved from Norrie. Deuce!

Almost shot of the tournament! Norrie hits a smash at the net which Tiafoe somehow half-volleys, but his effort drops just long. 40-30.

Jess Anderson
BBC Sport at Wimbledon

I said earlier that Sabalenka is a popular figure on the Tour but Wimbledon crowds love nothing more than an underdog and the huge roar as Bouzkova brought up break points tells you all you need to know about that.

A double fault from the world number one to concede the break prompts excited chatter among the punters.

Well, well, well. Is another big name is in trouble at SW19?

Aryna Sabalenka is broken and Marie Bouzkova will serve for the first set.

Bouzkova is going toe-to-toe with the world number one and is being rewarded.

She brings up the first break points of the match with a lovely forehand down the line and is gifted the break itself by a Sabalenka double fault.

Norrie saves the first as Tiafoe nets a backhand. 15-40.

Volleyed winner at the net from Tiafoe, who pumps his fist to the crowd after his winner.

Three chances.

Jonathan Jurejko
BBC Sport senior tennis reporter at Wimbledon

Job done! And done very well by Sonay Kartal at that.

Mightily impressive from the British number three, who reaches the Wimbledon third round for the second successive year.

Lots of confident, clean ball-striking from the baseline and scampering around her new favourite court with sharpness.

Next is 12th seed Diana Shnaider or French qualifier Diane Parry. All back to Court Three on Friday?

You can feel the momentum shifting. Norrie double-faults to slip to 0-30.

Two huge serves and a roar. Tiafoe holds.

Tiafoe gambles, going to the net, but Norrie whacks the ball straight to his opponent who readjusts to slap a volleyed winner.

But then Tiafoe nets. Another chance.