Aryna Sabalenka, unlike men's top seed Jannik Sinner, was on court for just 65 minutes.

It wasn't an entirely flawless performance but with 22 winners to 11 unforced errors (10-16 for Teodora Kostovic), 83% of points won behind her first serve, and five break points converted, it's a strong start.

Tracy Austin rated her performance an A-. Sabalenka goes for 8/10.

Barbora Krejcikova has the finishing line in her sights after breaking British wildcard Hannah Klugman in the second.

Klugman was broken in the third game of the second set to trail 2-1 and has been unable to hit back.

Krejcikova is potentially just a couple of games from booking her spot in round two.

Meanwhile on court 16, Briton Min Xu has been broken early in the third set and trails 3-0 against Daria Kasatkina.

Aryna Sabalenka appears to have taken that break of serve somewhat personally.

With a cross-court backhand winner, she earns two match points.

Eugenie Bouchard
Former Canadian tennis player on BBC One

Kostovic waving at the crowd to get them involved and as a 19-year-old, she has a lot of confidence to be acting that way out there. She looks and acts like she belongs.

Aryna Sabalenka saves the first break point with an ace but is passed easily on her forehand side after a tame approach to the net.

Teodora Kostovic offers a wave of celebration. She's broken the world number one on Centre Court.

Teodora Kostovic takes the opening point, showing mettle at the net, and she earns 15-30 with a forehand return winner. That rattled down the line.

Sabalenka nets a forehand.

Is there a twist in this match?

Aryna Sabalenka converts the second break point with a forehand winner, letting out a triumphant shout.

The world number one will serve for the match.

Image source, Getty Images

Mimi Xu struggled to find her groove in the opening set against Daria Kasatkina but the 18-year-old has settled into the second.

After a break of serve to lead 3-1, Xu consolidated and kicked on to take the set 6-3.

Over on court 12, fellow Briton Oliver Tarvet has lost 7-6 (7-4) 7-6 (7-4) 4-6 7-5 against French 25th seed Arthur Rinderknech.

Teodora Kostovic shakes her head as Aryna Sabalenka's backhand drop shot clips the net cord and dribbles over. She was flat-footed on the baseline anyway, so the head shake was more directed at the audacity of the stroke.

And in the blink of an eye, Sabalenka has two more break points.

With an ace and a booming first serve out wide which her opponent can only just get a racquet on, Aryna Sabalenka races to 30-0.

Teodora Kostovic wastes an opportunity with a loose forehand after getting into the point off a second serve.

Sabalenka closes out the hold with another big first serve.

Aryna Sabalenka seizes her first break point of the set, winding up for a forehand winner.

Down 15-30, Teodora Kostovic pulls out an ace - her third of the match.

But in a baseline exchange, she's let down by a loose forehand into the net. Break point.

Aryna Sabalenka races through a hold to love. She's only given up six points on serve across the match.

Annabel Croft
Former British number one on BBC 5 Sports Extra

I get the impression Kostovic has walked out on this court with the belief that she can beat the world number one. Considering the inexperience it is just surprising.

She doesn't walk, it's a march.

She knows her own mind.

Image source, PA Media

Tracy Austin
Two-time Grand Slam champion on BBC One

On being the top seed of a major tournament...

To me, I don't think it mattered if it was one or two, it mattered more how you felt. Were you prepared or full of confidence? I didn't put a lot of credit on the numbers - it's all about what's happening on the court and in between the ears.

Teodora Kostovic is in a little bit of disbelief at how she's not won that point... but her viciously angled forehand is hunted down by Aryna Sabalenka who executes a pinpoint drop shot at full stretch. 30-15.

Kostovic keeps her cool to hold to 30, coming on the approach off a wide serve and placing a forehand winner with more delicacy than you'd expect from someone with her intensity.

Keeping theme with how the day has been playing out, it's not looking good for British teenager Hannah Klugman.

The 17-year-old has lost the first set against 2024 champion Barbora Krejcikova on court three.

Czech Krejcikova saved a break point in the opening game before breaking Klugman twice en route to a taking the first set in 38 minutes.

Eugenie Bouchard
Former Canadian tennis player on BBC One

The thing about grass is once you're behind in the point it's hard to get back into it. When you're on clay you have more time.

It's hard to defend.

Aryna Sabalenka lets out a roar of delight as she follows a wide serve with a cross-court backhand winner down the same angle. 15-all.

She follows it with a smashed winner, draws a backhand error with an inside-out forehand, and watches on calmly as Teodora Kostovic buries a routine forehand in the net.