Serena Williams overcame illness -- and her semifinal opponent Timea Bacsinszky -- to reach the French Open tennis final.
Paris CNN  — 

A visibly ailing Serena Williams coughed throughout her semifinal match at the French Open, trudged to her chair during changeovers and once there, sought the respite of ice towels on the hottest day of a tournament blighted by cool temperatures and blustery winds. At times she was close to tears.

But nothing it seems can prevent Williams from capturing a 20th grand slam title and third in Paris.

She overturned set deficits in the second, third and fourth rounds, and on Thursday fended off illness – plus an opponent playing the finest tennis of her career.

The world No. 1 battled in typical fashion to force a third set and prevailed 4-6 6-3 6-0 over 23rd-seed Timea Bacsinszky to set up an encounter with Lucie Safarova in Saturday’s conclusion to the women’s event.

Her condition wasn’t much better by the time the near two-hour contest ended. She had to cut short her on-court interview post match because the cough returned, perhaps afflicted by the same illness that struck 2014 champion Maria Sharapova.

And she was a no-show for the usually mandatory post-match press conference, issuing a statement instead.

“I have been feeling unwell for a few days, and after this tough match against Timea, I needed to see the tournament doctor,” Williams said.

“I am proud to be back in the final here at Roland Garros, in a city that means so much to me, and am determined to be 100% ready for the final against Lucie on Saturday,” added the American, who owns an apartment in Paris and is coached by Frenchman Patrick Mouratoglou.

Safarova, unlike Williams, has yet to drop a set after seeing off Ana Ivanovic 7-5 7-5 in the first semifinal on Philippe-Chatrier court. A tall, big-hitting left-hander from the Czech Republic making the finale wouldn’t have surprised many but instead of Wimbledon champion Petra Kvitova it’s the 13th seed.

Williams won for the 24th time in 27 attempts in a grand slam semifinal. Her only conquerors? Justine Henin, Kim Clijsters and older sister Venus, a multiple grand slam winning trio.

If she achieves that 20th major, it would place the 33-year-old second in the Open Era only behind Steffi Graf’s 22. A rest day Friday could help Williams recover, and she leads Safarova – who will make her debut in a grand slam final – 8-0 in their head-to-heads.

Bacsinszky, who quit tennis more than two years ago to pursue a career in the hotel industry, orchestrated a five-star performance in the early stages, aided by Williams’ lethargy. Bludgeoning power on her backhand and mixing in drop shots contributed to Williams’ misery.

But after Bacsinszky – whose 15-match winning streak was stopped by Williams in March – broke for 3-2 in the second set, she didn’t claim another game.

Williams awoke and Bacsinszky’s weaker forehand side crumbled. When the Swiss missed two easy forehands to get broken to begin the third, there was realistically no chance of a comeback: Williams hadn’t lost a third set since last August.

“Well maybe she struggled but at the end she’s the winner of the match,” Bacsinszky told reporters.

Ivanovic ousted Safarova on the way to collecting her first and only grand slam crown in Paris in 2008 but their meeting last year at Roland Garros proved to be more of a predictor for this year’s outcome – Safarova triumphed in straight sets in the third round.

“It’s slowly sinking in and it’s just amazing,” Safarova said of making a grand slam final. “The happiness is unreal.”

She famously missed a match point fractionally long against eventual champion Li Na at last year’s Australian Open but hasn’t let the disappointment linger.

Safarova made the semifinals at Wimbledon, helped the Czech Republic win the Fed Cup in November and this March achieved a career-high of No. 11.

Just by landing in the semis in Paris, she was sure to move into the top 10.

“I think she’s always known she’s had the potential,” Safarova’s coach, Rob Steckley, told CNN this week. “She’s just maturing. We all do. As she matures and starts to grow, she realizes what she hasn’t done and what she has done and she kind of puts it together in a nice package now where she’s able to accept and take control.

“She took things a little bit too seriously before and put a bit too much pressure on herself. I think she’s just loosened up a lot. She’s enjoying the moment and trying to figure out from there how to keep trying to get better.

“And with each milestone I think she accomplishes, she gains more confidence and realizes that this is finally happening and that she belongs.”

Ivanovic – contesting her first grand slam semifinal since the 2008 French Open – started much the stronger. While she was sharp, though, Safarova committed a flurry of unforced errors.

Ivanovic paid the price, however, for not capitalizing when she held two break points at 4-1. Then leading 5-2, she wouldn’t win another game in the first, striking two double faults at 5-5 to trail for the first time.

Clutch serving rescued Safarova at 0-1 in the second and a deflated Ivanovic was broken in the ensuing game.

They moved along until a dramatic 10th game.

Serving for the match at 5-4, Safarova hit three double faults, one on match point. The crowd, wanting a third set, roared with delight as Ivanovic leveled. But their joy was short-lived.

Safarova quickly broke back and on her second attempt got the job done, sealing the contest with an inside-out forehand before dropping to the clay. Playing in the women’s doubles semifinals Friday, she won’t have a day off.

“I will try to just really enjoy it and relax,” said Safarova.

The men take center stage Friday. Novak Djokovic seeks to build on the momentum he garnered after handing nine-time champion Rafael Nadal only his second French Open loss in 72 matches Wednesday. The world No. 1 meets Andy Murray, who he has topped on seven straight occasions. Both men are unbeaten on clay this season.

The locals will be especially involved when Jo-Wilfried Tsonga faces 2014 Australian Open winner Stan Wawrinka. Tsonga bids to become the first French man to make the final at Roland Garros since Henri Leconte in 1988.

Read: Novak dethrones “King of Clay”