One player staged a great escape in what was arguably the best match of the tournament so far.
Another then strolled to victory against the world No. 1 in the match that followed, despite the knowledge that even a momentous win would not be rewarded with a place in the final four.
An incredible comeback by Caroline Garcia over Caroline Wozniacki (0-6, 6-3, 7-5) - coupled with an upset by Elina Svitolina over Simona Halep (6-3, 6-4) - ensured that the remaining semi-final spot in the Red Group went to the unlikeliest of candidates.
Frenchwoman Garcia will play American Venus Williams today in the semi-finals of the BNP Paribas WTA Finals Singapore presented by SC Global - as group winner no less - while Wozniacki of Denmark will play Czech Karolina Pliskova.
It is a turn of events that Garcia herself did not consider, having started the day needing a victory that was not even a guarantee of survival. She was also the last to qualify for the season-ender.
Told in her post-match media conference that she could be playing the American today, the 24-year-old responded with disbelief.
- Points swing from the first set to the second, when she had 35, as Caroline Garcia turned the match around..
"Yeah? I don't even know. If I make it through, I'm No. 1 (in the group)? Okay, why not," she said with a smile.
She ought to be pleased. Yesterday, from winning a measly seven points in the first set when Wozniacki dished out her third bagel in as many matches, Garcia stepped up considerably to win 35 in the following set, breaking Wozniacki's serve thrice in the second set. It was the first time that the Dane had not been able to hold serve this week.
More significantly, Garcia dug herself out of trouble when 3-5 down in the deciding set, then fought off three break points for a crucial 6-5 hold before eventually breaking Wozniacki for the win.
Said Garcia: "I was feeling like she (Wozniacki) was missing nothing. She was reading very well my game... I kept the intensity on and kept trying to find a way. I'm happy that when the battle is on, I'm fighting and I find a way to come back."
Yesterday's win was her second victory in the group stage. The other, against Svitolina on Wednesday, had involved a similar comeback from 3-5 down in the rubber.
The latter, already eliminated before stepping on court, did Garcia a favour by beating Halep, thereby also gaining the satisfaction of ending her season with a win against the world's top-ranked player.
Knowing that it would be her final match of the season made it easier to play freely, said the Ukrainian world No. 4 after the match.
But while Svitolina played without inhibition, Halep struggled for rhythm. She admitted later: "Today I just felt 100 per cent that the court is not for me and I cannot finish a point. It's not going."
Indeed, it was just not the world No. 1's day. Even when arriving for her post-match media conference, the Romanian came close to falling when she almost missed a step.
Still, she is not about to let another edition of the season finale - she has now failed to make the last four for three years in a row - be a dampener on her season.
She said: "Even if I did the same result here, I'm a different player and I'm stronger.
"I will not let this tournament ruin everything I built this year, so I'm looking forward to the next year to have a good, a better start."
Day7, s-finals: StarHub Ch203, 1.30pm & 7.30pm