PARIS -- The ball landing at Barbora Krejcikova's feet on match point appeared to come down behind the baseline.
The linesman thought so and called the shot long. A TV replay confirmed as much, and the unseeded Krejcikova was so sure she raised her arms in triumph to celebrate a berth in her first Grand Slam final at the French Open.
Chair umpire Pierre Bacchi disagreed. He reversed the call, sparking a fresh round of debate about video replay and briefly delaying Krejcikova's victory.
Tennis was spared an unjust result five points later, when she hit a backhand winner to close out the biggest victory of her career. The Czech saved a match point midway through the final set and outlasted No. 17-seeded Maria Sakkari of Greece, 7-5, 4-6, 9-7.
"I always wanted to play matches like this,'' Krejcikova said.
She must like roller coasters too. Her opponent Saturday will be 29-year-old Russian Anastasia Pavlyuchenkova, who also advanced to her first major final by beating unseeded Tamara Zidansek, 7-5, 6-3.
It was only the second time in the professional era that there were four first-time Grand Slam women semifinalists at a major tournament, and the first time since the 1978 Australian Open.
The men's semifinals Friday include a showdown between 13-time champion Rafael Nadal and 2016 winner Novak Djokovic. It's their 58th meeting, and a rematch of last year's Roland Garros final. The other semifinal will match No. 5 Stefanos Tsitsipas against No. 6 Alexander Zverev, and one of them will have a shot Sunday at his first Grand Slam title.
Krejcikova, a two-time major doubles champion ranked 33rd, is playing singles in the main draw of a major tournament for just the fifth time. The No. 31-seeded Pavlyuchenkova, by contrast, has played in more majors before reaching a final -- 52 -- than any other woman.
A top-20 player as a teen, Pavlyuchenkova had been 0-6 in major quarterfinals before finally surmounting that hurdle on Tuesday, and was steadier than the big-swinging Zidansek in their semifinal.
"I wanted this so much that right now I don't feel anything,'' Pavlyuchenkova told the crowd in French. Krejcikova's run to the final is equally improbable.
"It sounds incredible,'' she said. "I cannot believe it. It's actually happening."
It seemed especially unlikely nine games into the third set, when Sakkari held a match point. She confessed she then became less aggressive.
"I got stressed, starting thinking that I'm a point away from being in the final,'' she said. "I guess it's a rookie mistake.''
Krejcikova erased the match point with a swinging volley for a nervy winner, and 40 minutes later they were still playing.
Then came the real drama. With Krejcikova holding a match point in the final game, Sakkari hit a forehand near the baseline. Bacchi climbed off his chair, took a look, called the shot good and ordered the point replayed.
"He came and he's like, 'It's in,' and I'm like, 'No, no, no, no, no, no. Why?''' she said with a chuckle. "But what can I do? I cannot change his decision. It's fine; let's go. Let's try to just win the next one.''
A TV replay indicated the ball was clearly long, but video review isn't used at Roland Garros, where the balls usually leave clear marks in the clay.
Krejcikova kept her cool and was celebrating for good moments later after converting her fifth match point.
There wasn't as much drama in the day's first match, but the quality of play was as enjoyable as the warm, cloudless weather. The 85th-ranked Zidansek, who this week became the first Slovenian woman to reach a Grand Slam quarterfinal, was the better player for much of the first set, moving well and hitting the more aggressive groundstrokes.
But Pavlyuchenkova won the most important points, and Zidansek dumped consecutive shaky serves into the net to lose the set.
Pavlyuchenkova's groundstrokes carried more sting in the second set as she raced to a 4-1 lead. Her first sign of nerves came as she double-faulted twice, including on break point, to make it 4-3, but she broke back and easily served out the victory.
"Tennis is such a mental sport," she said. "That's what is really hard about tennis.''
Zidansek could only agree.
"A new situation for me, semifinals of a Grand Slam,'' she said. "So, yeah, I was nervous. But who isn't at this point? I was just trying to compose my nerves as well as I could.''
Pavlyuchenkova, who has won 12 tour titles, will climb back into the Top 20 next week for first time since January 2018.
"She's in the final,'' Krejcikova said. "She must be playing well.''
The same could be said for Krejcikova, who has won 11 consecutive matches, including her first WTA singles title last month at Strasbourg. She is the eighth unseeded women's finalist at the French Open in the professional era, and the fourth in the past five years.
A protege of the late Grand Slam champion Jana Novotna, Krejcikova seeks to become the first Czech woman to win Roland Garros since Hana Mandlikova in 1981.