Watch and follow BBC TV and radio coverage of day nine of Wimbledon (UK only)
GB's Cameron Norrie comprehensively beaten 2-6 3-6 3-6 by defending champion Carlos Alcaraz
World number one Aryna Sabalenka wins 4-6 6-2 6-4 against Laura Siegemund in quarter-finals
Amanda Anisimova wins 6-1 7-6 (11-9) against Anastasia Pavlyuchenkova
Taylor Fritz first player through to singles semi-finals, winning 6-3 6-4 1-6 7-6 (7-4) against Karen Khachanov
Britain's Alfie Hewett starts wheelchair title defence with 6-1 6-2 win over Daniel Caverzaschi, Gordon Reid also through
Sir Ian McKellen (or Gandalf to fans of the Lord of the Rings films) is keeping a close eye on proceedings from the Royal Box on Centre Court where top women's seed Aryna Sabalenka is a set down to world number 104 Laura Siegemund...
Image source, Getty Images*Sabalenka 4-6 4-2 Siegemund
Tracy Austin
Two-time Grand Slam champion on BBC One
That is a massive game and it will give Sabalenka so much momentum.
There is a huge power difference between the two players. Siegemund's first serve is about 54 percent down the middle of the box.
Sabalenka has taken a little bit of speed off her returns to make sure that more go in. She is looking for more consistency than power. Good patience from her.
*Sabalenka 4-6 4-2 Siegemund
Image source, EPABig moment.
Aryna Sabalenka comes back from 40-0 down to go a break up again in this second set.
It's frustration for Laura Siegemund, who double faulted to make it 40-15 and then failed to put away a passing shot at 40-30.
Sabalenka uses her power well, though, and moves her opponent side to side before Siegemund's backhand sails long to give the top seed the break.
*Fritz 6-3 6-4 1-6 2-2 Khachanov
We're back on serve in the fourth set.
Karen Khachanov saves the first break point but hits his backhand wide to give up the second. Taylor Fritz slipped a couple of times on the backhand side during that game and Khachanov lost the point both times.
*Fritz 6-3 6-4 1-6 1-2 Khachanov
Taylor Fritz is beginning to purr. A gorgeous down the line backhand gives him 0-15 before Karen Khachanov fails to capitalise on his opponent slipping, underhitting a cute shot into the net.
The Russian hits back with an ace but now finds himself facing two break points.
Sabalenka 4-6 3-2 Siegemund*
Annabel Croft
Former British number one on BBC Radio 5 Live
Image source, Getty ImagesI don't feel like Sabalenka is hitting her forehand very well - she is pushing it and it's got no power. She is coming right up the back of the ball and it's not doing any damage at all, it is giving Siegemund plenty of time down the other end.
Fritz 6-3 6-4 1-6 1-2 Khachanov*
Gary Rose
BBC Sport at Wimbledon
Lots of uncertainty and confusion in the crowd after the issue with the electronic line call system and there's a few groans at the decision to replay the point.
But this continues to be a worrying run for Taylor Fritz as he finds himself a break down at the start of a set once again.
Fritz 6-3 6-4 1-6 1-2 Khachanov*
Taylor Fritz's movement doesn't seem to be too impaired by the heavy strapping around his toes. He charges into the net to take a 30-15 lead.
Karen Khachanov pulls it back to 40-30 but Fritz nails an ace to get on the board in the fourth set.
Sabalenka 4-6 3-2 Siegemund*
Tracy Austin
Two-time Grand Slam champion on BBC One
Siegemund has no trouble with a backhand return. That's an insane angle she was able to hit to get herself back to 40-30.
If I was Sabalenka, I would take a little bit of pace off just to ensure that first serve.
*Fritz 6-3 6-4 1-6 0-2 Khachanov
Taylor Fritz rocks his head back in frustration as he buries a shot in the net to fall 30-0 behind.
With an ace, Karen Khachanov is up 40-0 before Fritz hits the net again.
Khachanov pumps his fist. Momentum has well and truly swung in his favour.
Sabalenka 4-6 3-2 Siegemund*
Aryna Sabalenka holds but nothing is coming easily for the world number one.
It might not have felt that way when she swiftly got to 40-0 but Laura Siegemund slaps a backhand return down the line to make it 40-15 and in a flash, it's deuce.
Sabalenka manages to come through as Siegemund finds the net, though. An important hold.
Fritz 6-3 6-4 1-6 0-1 Khachanov*
Karen Khachanov only needs one of his two break points, with Taylor Fritz hitting wide.
Khachanov has already won two five-setters (in rounds two and three) on his run to the last eight.
*Fritz 6-3 6-4 1-6 0-0 Khachanov
Image source, Getty ImagesTaylor Fritz's feet got quite a lot of attention during the break. He had the trainer out restrapping his toes.
The second point of the game has to be replayed after a rogue interruption from the electronic line call system. The umpire calls it a "malfunction".
Karen Khachanov wins the replayed point and takes a 15-30 lead after his drop shot lures Fritz into the net and creates space for a passing shot.
And now the American is facing two break points.
*Sabalenka 4-6 2-2 Siegemund
Tracy Austin
Two-time Grand Slam champion on BBC One
What a start to this second set. Siegemund is throwing everything but the kitchen sink at Sabalenka.
The slow balls are getting to the Belarusian. For her, you don't want to show how distraught you are.
*Sabalenka 4-6 2-2 Siegemund
Laura Siegemund races to the net and puts the ball away for a winner to hold to love.
She tumbles to the ground as she hits it, stopping just short of the net, but she won't mind that.
The unseeded German is back level in the second set.
Sabalenka 4-6 2-1 Siegemund*
Image source, PA Media"Come on!" shouts Laura Siegemund as she gets the immediate break back.
The German had earned two break points with another gorgeous drop shot and a backhand winner down the line but a pair of big serves from Aryna Sabalenka take it to deuce.
Siegemund earns another, though, and when Sabalenka's forehand drifts long, Richard E Grant is among those enthusiastically celebrating the break for the underdog.
Fritz 6-3 6-4 1-6 0-0 Khachanov
Gary Rose
BBC Sport at Wimbledon
I can only assume Taylor Fritz's serve hopped off and went for a hotdog in that third set because it absolutely deserted him. What a bizarre capitulation after being so composed for two sets.
With three of his four matches at Wimbledon so far going to at least four sets - and the other seeing his opponent retire - perhaps we should have known he'd have us hanging around here longer.
*Fritz 6-3 6-4 1-6 0-0 Khachanov
Image source, PA MediaKaren Khachanov wastes no time in sealing the third set, racing to a 40-0 lead with a smashed winner at the net the pick of the shots.
Taylor Fritz pulls it back to 40-15 but Khachanov is unfazed.
That set took just 28 minutes and the trainer is coming on for Fritz.
Paldanius 6-3 6-0 Hewitt
Image source, Getty ImagesSeeing Cruz Hewitt - son of 2002 men's singles champion Lleyton - playing on the same courts as his father this week will have made many suddenly feel quite old.
On Sunday, the 16-year-old was victorious on his first appearance at Wimbledon when he beat Savva Rybkin 6-1 6-2 in the first round of the boy's singles competition - 23 years after Lleyton won the men's title.
However, a dream-run on the famous grass courts at SW19 was not be for the teenager after he lost to Finland's Oskari Paldanius in straight sets on Tuesday.
I'm sure we will be hearing that name mentioned plenty more times around these grounds in the future.
Fritz 6-3 6-4 1-5 Khachanov*
Taylor Fritz needed that!
He gave up the first advantage but gets a second bite at the cherry with a forehand winner down the line. He seals the game with a welcome ace and avoids the bagel.
Karen Khachanov will serve for the third set.
