Serena Williams survived another struggle to set up a French Open final against Garbine Muguruza.

The world number one is now within one victory of equalling Steffi Graf’s Open era record of 22 grand slam singles titles.

Williams’ semi-final against unseeded Dutchwoman Kiki Bertens was more a case of survival of the fittest than a tennis match, with both women appearing far from 100 per cent.

Perhaps that was not too surprising given this was their third match in as many days, and Williams must now focus on recovering for the final on Saturday.

Bertens, who considered not starting the match because of a left calf problem, served for the first set and had two set points but eventually went down 7-6 (9/7) 6-4.

Muguruza, meanwhile, defeated 2010 finalist Sam Stosur 6-2 6-4 to set up a repeat of last year’s Wimbledon final, which she lost to Williams.

It was the end to a dream three weeks for Bertens, who arrived in Nuremberg for a tournament the week before the French Open ranked 89th.

She won the title there as a qualifier and took that form into Roland Garros, beating Australian Open champion Angelique Kerber, Madison Keys and Timea Bacsinszky on her way to her first grand slam semi-final.

Her 12-match winning run will see her climb inside the top 30 and should mean she is seeded for Wimbledon.

Williams was nearly two hours late for her press conference on Thursday after fighting past Yulia Putintseva in three sets but insisted she was not struggling with any injury.

But, speaking on ITV4, former Wimbledon champion Marion Bartoli claimed Williams was battling a thigh problem, and the top seed certainly was not moving well at the start of the match.

If both players has muscular issues, then the weather certainly would not have helped.

Court Philippe Chatrier was embarrassingly empty despite tickets selling out quickly, and those spectators who were in the stands were wrapped up against the cold.

Both players were wearing long-sleeved tops and leggings, which did not help their sluggish movement.

Bertens made the better start and Williams did well to stay within one break of the Dutchwoman, who had two chances to lead 4-1.

Bertens then had a set point with the American serving at 5-3 but netted a makeable forehand.

Williams gave a hint of what was troubling her when, chasing a short ball, she appeared to drag her right leg and then hop in pain.

But, with Bertens also struggling physically, Williams was finding the drop shot effective and she levelled at 5-5.

A poor volley cost Williams on her first set point but, after saving another Bertens chance, she took her second opportunity with a big serve and forehand into the open court.

The 34-year-old had been strangely silent, wearing a look of resignation, but at last she unleashed a ferocious scream.

Bertens won the opening two games of the second set but Williams quickly hit back and, having seen three match points go begging on the Dutchwoman’s serve, took the fourth when Bertens hit a forehand just long.

Since losing her first set of the tournament to Anna Karolina Schmiedlova, Muguruza has barely put a foot wrong and overpowered 2010 finalist Stosur.

Muguruza looked like she might wobble when she was pegged back from 5-2 to 5-4 in the second set but two aces took her to match point and the Spaniard clinched victory when Stosur netted a forehand.

The 22-year-old, a quarter-finalist at Roland Garros the last two years, is the first Spanish woman to make the French Open final since Conchita Martinez 16 years ago.