Ooof, that's more like it from Karen Khachanov.

One of his best shots of the match, a creamed backhand winner down the line, helps to keep us on serve in the second set on Court One.

Image source, EPA

Taylor Fritz serves his second double fault of the match but that's a rare blip by the American on serve.

Another routine hold.

Pat Cash
Former Wimbledon champion on BBC Radio 5 Live

Interestingly, Sabalenka has gone up to the last few drop shots and drop shotted back. She is picking that up quite quickly, she was certainly fooled by the first few.

It is a big part of Siegemund's game so if Sabalenka can neutralise that and win some points, that is a big win for Sabalenka.

Tracy Austin
Two-time Grand Slam champion on BBC One

Sabalenka needs to counter the slices from Siegemund and use them as an excuse to get to the net. That will be an advantage for the world number one. The chip return from Siegmund is also an opportunity for Sabalenka to get ahead of the point.

Aryna has certainly been the most consistent player in the WTA this year.

Image source, Getty Images

There's one break back for Aryna Sabalenka.

Impressive response from the top seed as she races in to reach another Laura Siegemund drop shot and respond with one of her own.

The German can't get to it and that brings up three break points.

Sabalenka only needs one, quickly getting on top in the point before firing a forehand into the open court with Siegemund well beaten.

Karen Khachanov finds a powerful backhand to wrap up the game and move narrowly in front once again in the second set.

Tracy Austin
Two-time Grand Slam champion on BBC One

Siegemund has come out flying here. What an opening.

She is looking very calm and is playing with the perfect offensive balance. You never know what is coming next from Siegemund, I would hate to play her. She has you on a string when she is playing her best.

Annabel Croft
Former British number one on BBC Radio 5 Live

It is really old fashioned, 80s style tennis from Siegemund. It is very intelligent and is outfoxing Sabalenka.

Sabalenka normally walks tall around the court but she is looking a little deflated at the moment. She is trying not to get upset with herself, but you know she is bubbling under the surface.

Amy Lofthouse
BBC Sport at Wimbledon

The noise from the Centre Court crowd has gone up a notch after another stunning return winner from Laura Siegemund to go a double break up.

It's early days, but she just looks so much more confident right now than Aryna Sabalenka, who has already thrown a "what am I supposed to do?" shrug of the shoulders towards her box.

Image source, Reuters

Goodness me, Laura Siegemund is flying in the opening exchanges!

Another fabulous drop shot gets her started against the Aryna Sabalenka serve, that's what we've come to expect from the German.

She's not really known for her power but a couple of brutal and perfectly-placed groundstrokes ensure the double break.

The first an inside-out forehand that fizzes past Sabalenka before a remarkable return winner that has the top seed grasping at thin air.

While Karen Khachanov is being made to work very hard during his service games, Taylor Fritz is blitzing through his.

Karen Khachanov gets a bit of fortune with a net cord and that secures an important hold for the 17th seed, who desperately needed to avoid falling behind early in set two.

Tracy Austin
Two-time Grand Slam champion on BBC One

Siegemund's movement is top-class. She is so nimble. She doesn't have the power but she has the ability to defend. She makes you think so much because she is so unpredictable with what shot she plays.

Sabalenka wants to be dictating and be hitting hard enough that Siegemund can't be using all of her court craft.

Impressive hold for Laura Siegemund with Aryna Sabalenka pushing to break back immediately.

The world number one forces a break point as she attacks the Siegemund forehand.

But she a puts backhand into the net on break point and Siegemund is able to grind it out from there.

Marion Bartoli
Former Wimbledon champion on BBC Radio 5 Live and BBC Sounds

Total dominance from Taylor Fritz is because he is not missing a ball - only four unforced errors throughout the entire first set and 11 for Khachanov. The way he is striking the ball, he isn't giving Khachanov a single opportunity for a break point. He had zero chance to win that first set.

Break point number three of the game saved - back to deuce.

Another break point for Karen Khachanov to save now, as the Russian goes long during another lengthy rally.

Amy Lofthouse
BBC Sport at Wimbledon

I'm never hugely convinced you can tell much from a warm-up, but when Aryna Sabalenka was hitting some practice serves, Laura Siegemund mullered two backhand return winners - almost exactly as she did just then to break the world number one in the first game.

Annabel Croft
Former British number one on BBC Radio 5 Live

I think Siegemund already is [troubling Sabalenka]. She is chipping some of these returns and really nullifying the powerful service motion that she has. She is throwing in some horrible, nasty drop shots. She is a wily player.

Karen Khachanov saves the first break point by putting away a volley at the net, but Taylor Fritz will get a look at a second serve on the second break point...

A lengthy rally ensues - and it's Fritz who goes marginally long with a forehand.

Deuce.