Tournament favourite Serena Williams will face Maria Sharapova in the last four at Wimbledon following her fiercely contested quarter-final win over former world number one Victoria Azarenka.
Azarenka, whose only two grand slam victories to date both came at the Australian Open, took the second of two break points in the fourth game before maintaining her composure to win the first set 6-3 amid a furious exchange of powerful groundstrokes.
The Belarusian lost to Williams in the final of the US Open in 2012 and 2013 as well as in the third round of the French Open at Roland Garros in June and defeat looked possible once again as she struggled badly on her own serve to drop the second by a wide margin.
Williams grabbed a crucial break to take a 2-0 lead in the third set and never really looked back as she closed out a 3-6, 6-2, 6-3 victory in typically dominant fashion.
"It was really fun out there," she said. "I was smiling at one point and I saw Victoria smiling as well. We both really enjoyed it. It's been up and down, up and down but somehow I'm still alive. I'm just happy to be here."
Sharapova possesses a frankly dismal 2-17 head-to-head record against Williams, so will no doubt have preferred to see Azarenka progress following her own somewhat unconvincing triumph against Coco Vandeweghe.
The 2004 Wimbledon champion dropped the second set against her unseeded opponent, but did enough to advance 6-3, 6-7, 6-2. After the match, Sharapova conceded she briefly lost control but declared herself delighted to be back in the semi-finals at the All England Club for the first time in four years.
She told the BBC: "I was pretty dominant in the first set and the beginning of the second but things slipped away after that and I had to regroup. My opponent was full of confidence so I knew it was going to be a tough match.
"You're in a position to win it and sometimes it doesn't quite go your way. You have to go back to what worked for you in the first set. You have to give everything, you are playing in a Wimbledon quarter-final. It's been a while since I have been in a semi at Wimbledon, I was pleased to win today and it gives me a lot of confidence."
Elsewhere at SW19, Spaniard Garbine Muguruza followed up her upsets of Angelique Kerber and Caroline Wozniacki by progressing through to the first grand slam semi-final of her career after knocking out 15th seed Timea Bacsinszky.
Muguruza, currently ranked 20th in the world, had never previously advanced beyond the second round but won 7-5, 6-3 in straight sets.
"It is just amazing. I am so happy," she said. "It was a very tough match and I am just so excited. It was a very intense final game so it is just relief. It is very hard to make the last four of Wimbledon so to achieve this so I am very proud."
Awaiting Muguruza next is Agnieszka Radwanska, with the beaten 2012 finalist having seen off Madison Keys 7-6, 3-6, 6-3.
In the conclusion of the men's fourth round tie between Novak Djokovic and Kevin Anderson, the defending champion added the finishing touches to a quite remarkable comeback to win in five sets, 6-7, 6-7, 6-1, 6-4, 7-5. He will play Marin Cilic in the quarter-finals.