Czech seventh seed Tomas Berdych bounced back from a set and a break down to win a place in the semi-finals of the ATP World Tour Finals with a 3-6, 7-5, 6-1 victory over Spain's David Ferrer on Friday.
Berdych finished as Group A winner and will play France's Jo-Wilfried Tsonga in Saturday's semi-finals.
Ferrer, who had already qualified, takes on defending champion Roger Federer in the last four.
Berdych is through to the semi-finals for the first time after going out in the group stages on his debut last year, and he insisted the pressure of having things in his hands had not been a factor.
"I don't like all the different possibilities so I didn't even look at that. For me it didn't change anything," he said.
"It would have been nice to finish the season winning the match even if I hadn't gone through.
"But it's better still to end up winning. I won. I won the group. Perfect."
Ferrer has a woeful record against Federer and must also return to the court less than 16 hours after finishing the Berdych match as he has been scheduled to play the early semi-final.
"Tomorrow I will try to do my best," Ferrer said. "I will try to fight a lot. I've never beaten Roger, and I hope I can change that."
Djokovic's defeat against Janko Tipsarevic earlier in the day meant Berdych was certain to qualify in first place if he could beat Ferrer.
There was significant motivation for both players to finish top of the group since it would mean avoiding a semi-final showdown with 16-time Grand Slam champion Federer.
Neither player was willing to give an inch for much of the first set but it was Ferrer who landed the decisive blow.
A superb backhand down the line gave him the first two break points of the match and he needed only one to take the lead when Berdych's forehand drifted wide.
Ferrer has been in fine form this week, handing Djokovic the heaviest defeat suffered by any world number one in over 28 years when he beat the Serb 6-3, 6-1.
The Spaniard, who had won his previous four meetings with Berdych, broke in the third game of a rollercoaster second set.
But Berdych hit straight back to level at 2-2 with an angled volley on his third break-point in the next game.
Ferrer looked in control when he broke for a 4-3 lead, yet the world number five then lost his composure as Berdych unloaded some big ground-strokes to come from 40-15 down to break again.
Berdych was playing with real freedom now and he snatched the set from Ferrer's grasp with another break at 6-5.
Ferrer changed into a lurid pink top for the final set but the switch didn't bring him any luck as a double fault in the first game presented Berdych with the decisive break.
After being out-played for the first set and a half, Berdych was suddenly within touching distance of an unlikely semi-final berth and he moved even closer when Ferrer double-faulted to fall 4-0 behind.
Berdych's serve was working too well to blow that lead and the Czech was soon celebrating his spot in the last four.