ISTANBUL, Turkey - With a spot in the semifinals on the line they weren't about to give ground - and they really didn't, literally, chasing down every shot they could over three hours and 29 minutes, the longest best-of-three-set match in WTA Championships history. But at the end there could only be one winner and it was Agnieszka Radwanska, who outlasted Sara Errani, 67(6) 75 64.
The No.7-ranked Errani walked into the match against the World No.4 in a very deep statistical hole, a dubious 0-22 record against Top 5 players. But it was hard to see that early on as she not only closed out a tense 74-minute first set, but also went up 2-0 in the second set - she was even a game away from victory, saving a slew of break points at 4-all and holding for 5-4 second set.
But Radwanska wasn't about to make it 23rd time lucky for Errani - the Polish star reeled off the next three games in a row, all at love, and then extended that streak to six games in a row to build a 3-0 lead in the third. Errani was not finished, winning four of the next six games to close to 5-4, but Radwanska managed one last hold to close it out and move into the semifinals.
"After my last match I wasn't that fresh, so I was afraid of what would happen," Radwanska said in her on-court interview. "I don't know how I did it today, especially after almost three and a half hours on the court, but I'm so happy.
"Now I'll try to do a lot of treatment to stay in one piece!"
"I was dead maybe from the second set, but I just tried to keep fighting," Errani said. "In tennis you have to fight. I just tried to play point by point - even if I was tired, it doesn't matter. I just thought about fighting, and not other things.
"But this is tennis. You win or you lose, and that's it."
Radwanska was just a bit more aggressive in the key moments, more inclined to finish the points off at net and take shots out of the air (Radwanska was 37 of 55 at net, Errani 27 of 36). Radwanska also had cleaner overall numbers, with a +10 differential of winners to errors (53 to 43) while Errani was +2 (49 to 47).
At the end of the day Radwanska moved through to the semifinals of the WTA Championships for the first time, having fallen in the round robin stage in all three previous appearances here (as an alternate in 2008 and 2009, and as a direct entrant in 2011). She will now play the World No.3, Serena Williams.
"Obviously Serena's a great champion - in that kind of match I have nothing to lose, so I'll just go on court and enjoy it," Radwanska said. "I've had a lot of tennis the last few days and it's really hard to play like this every day.
"I'll try my best, but we'll see how it's going to be!"
Williams has beaten Radwanska in all three of their previous meetings, the last one going to three sets (though Williams did lead 61 42 in that match).
Radwanska talked about that last meeting with Williams, which was in this year's Wimbledon final. "Well for sure when I was going on the Centre Court it was a different feeling than the usual final - it was amazing, just a dream come true when you go on Centre Court on the last day of a Grand Slam. It was a great experience, so for sure I will remember that moment for a long time."