Seven-time champion Serena Williams is just two wins away from equalling Margaret Court’s Grand Slam titles record of 24 but she wobbled several times in her Wimbledon quarter-final against Alison Riske on Tuesday.

The 37-year-old, who recorded her 97th success at Wimbledon to move second on the women’s all-time list, came under enormous pressure from her fellow American before prevailing in an engrossing contest, 6-4, 4-6, 6-3 in just over two hours.

Williams will play either Britain’s French Open semi-finalist Johanna Konta or Czech veteran Barbora Strycova in Thursday’s semi-finals which will be her 12th at the tournament.

“It was really satisfying,” said Williams, whose clay court campaign was affected by a knee injury.

“I wouldn’t have won that match a couple of weeks ago.”

Also joining her in the last four was Romania’s former world number one Simona Halep, who fought back from 4-1 down and three break points in the first set to beat China’s Zhang Shuai 7-6 (7/4), 6-1.

For Halep — who aside from Williams was the only player in the quarter-finals to have won a Grand Slam, taking the French Open last year — it is her second Wimbledon semi-final.

Williams, whose total of 97 Wimbledon wins compares to the 81 combined of the other seven quarter-finalists, will look back on her win with some relief.

Riske converted all five of her break points while Williams succeeded with just six of her 16 opportunities.

However, she relied on her power to keep her in the match.

In doing so she managed to avoid the fate that befell world number one Ashleigh Barty at the hands of Riske on Monday.

“I’m glad that I was able to come through,” said Williams.

“She beat so many great players. She was really so close to taking the win today.”

‘Just button up’

Williams was constantly cajoling herself and letting out roars of come on during the match.

Having sealed the match she turned to the players box where she was supported by older sister Venus and her husband, Reddit co-founder Alexis Ohanian, and yelled, pumping her fists.

“I was really pumped, it was for a place in the semis at Wimbledon — that doesn’t happen every day and it’s a long, arduous road,” said Williams.

“I just had to just button up and play hard.

“She was playing her heart out and she had nothing to lose and I realised neither did I.”

Halep, who ended the run of 15-year-old Coco Gauff on Monday, took the match by the scruff of the neck once she won the first set.

Halep, the seventh seeded former world number one, will face either Elina Svitolina, the eighth seed from Ukraine, or Karolina Muchova of the Czech Republic for a place in the final.

“I fought hard in the first set, even if I was down 4-1,” said 27-year-old Halep.

“I knew I had to be strong, play aggressive as much as possible and I did it great.

“I have energy, I feel fresh, I feel healthy, I feel confident when I step on the court.”