Jo-Wilfried Tsonga qualified for the last four of the ATP World Tour Finals with a 7-6 4-6 6-3 victory over Rafael Nadal.
It was a winner-takes-all match at the 02 Arena which lived up to expectations as the Frenchman won in just under three hours.
He goes through to a semi-final clash against another Spaniard in David Ferrer, while Nadal heads home.
The first set went with serve all the way to a tiebreak, which Nadal dominated to take 7-2.
The second set looked to be heading in the same direction before Tsonga seized the first break of the match in the 10th game to take it 6-4 and level the match.
The sixth seed had all the momentum now and he broke again in the third game of the decider. That became a double break and a 5-2 lead when a tiring Nadal dumped a simple forehand into the middle of the net.
Tsonga wobbled briefly as two double faults helped Nadal break straight back, but he upped his levels again in the next game as he raced to 0-40 and secured victory on his first match point.
Nadal had taken a month off prior to the tournament with next weekend's Davis Cup final against Argentina in mind, and he certainly lacked his usual sharpness.
Tsonga played a superb match, though, to reach the semi-finals for the first time, and he said:
"I just played amazing. It was not easy for me to come here against Rafa but I did it tonight and I'm very happy."