Serena Williams struggled into the semi-finals at Wimbledon on Tuesday in a patchy 6-4, 4-6, 6-3 defeat of Alison Riske.
The seven-time champion at the All England Club teetered on the edge several times during the two-hours battle, losing serve five times but converting on 10 of 16 break chances against her fellow American opponent.
Riske, who came to the court with more than nine cumulative hours of tennis in her legs, was unable to match her knockout of top seed and reigning Roland Garros winner Ash Barty in the previous round.
The 55th-ranked outsider lost to an opponent who had played just five hours in four previous matches.
The win by Williams was her 97th at Wimbledon and just 14th of the season.
“My big-match experience counted today” Williams said. “I had to play hard. She was playing her heart out and had nothing to lose – but neither did I.
“I just now need to do better.”
Williams trailed a break in the opening set but came back to take the early lead. In the second set a break for Riske was enough to square the contest.
The pair exchanged breaks in the first two games and again in the fourth and fifth games to stay level-pegging.
But a Riske double-fault spelled the end of the eight game, with Williams leading 5-3. The 11th seed served out the win with an ace on match point moments later.
Williams said that her injury-plagued season has meant that she is well behind on training and match form.
“This is the first time since Australia that I actually felt, like, good. It’s been a really, really long year for me already, and hard year, because I’m usually not typically injured,” she said.
“Now that I feel good, I can actually focus on training and technique and practice, something that I just literally haven’t been able to do a lot of.
“I just needed to just fight in the third set. Alison was not giving it to me. I needed to step up and take it.”
Riske said shew was outplayed by a champion. “I definitely gave it everything I had. I’m really proud of my effort today,” she said.
“I thought maybe I had a peek here and there at a couple openings. But Serena really upped her level, as only a champion would.
“She won the match. It was really actually very interesting for me to be on the opposite end because I felt her up her game and her intensity.”
Williams will clash on Thursday against Barbora Strycova, who dismissed Britain’s last hope Johanna Konta 7-6(5), 6-1.
“It’s sounds crazy, it’s happening but I can believe it,” the 33-year-old Czech who has been hinting at retirement, said.
“I’m extremely happy I’m shaking right now.”
Strycova came from 4-1 down in the opening set and never let Konta get a grip on the match.
“This was one of my best matches,” the winner said. “She was hitting hard, but I stuck to my game plan and tried to mix it up.
“I got into the match and was able to turn it around. I had never been on Centre Court before … this was a special moment for me.
Strycova has lost all three of her matches against Williams, but added: “I can’t wait to get on to the court.”
At the bottom of the draw, former No. 1 Simona Halep booked her first semi-final here since losing to Eugenie Bouchard five years ago, with the Romanian defeating Zhang Shuai 7-6(4), 6-1.
The Chinese player almost gave up her career in 2015 after poor results and came to Wimbledon for this edition without a win here from five appearances.
Her luck changed for the better last week, though it ran out against Halep, who levelled her record in the series to 2-2.
Zhang had lost her first 14 career Grand Slam matches; her quarter-final duplicated her best-ever performance, a last-eight place at the 2016 Australian Open.
“I expected her to play so well,” Halep said. “She beat me the last two times that we played.
“I was a little bit nervous before the match, a little bit stressed. I knew that she’s going to come and hit the balls very strong.
“It’s really tough to return against her, the balls don’t bounce so much.
“I knew that I have to be 100 per cent for every ball to break her rhythm.”
Halep will aim for the final as she plays Elina Svitolina for the eighth time, with the pair standing level in the series.
Svitolina, her right thigh heavily strapped and a loser in four Grand Slam quarter-finals, stopped 22-year-old Czech Karolina Muchova 7-5, 6-4 – but not without some difficulty.
The eighth seed was close to victory leading a set and 5-2, but was broken, she finally prevailed three games later to wrap it all up in 92 minutes.
“It’s amazing to be playing my first semi-final at a Grand Slam (on her 28th try),” Svitolina said, “I’m excited.
“I’m looking forward to the match already. It will hopefully be my first time on Centre Court, we’ll see.”
Svitolina trailed in the opening set and recovered but had to fend off a fightback from her opponent in the second, when Muchova made a move from 2-5 down.
“She’s a very tricky player, the grass suits her. I had to fight for every point.
“I had to put that one extra ball over the net to win.”
Muchova, who went to the net more than 20 times. went down to defeat with a costly 31 unforced errors which marred her attacking game.