Rafael Nadal set up a blockbuster semi-final against Andy Murray at the Barclays ATP World Tour Finals by making it three Group A wins out of three against Tomas Berdych in London this afternoon.
After seeing off Andy Roddick and Novak Djokovic on the O2 Arena court where he failed to win a set last year, the world number one defeated Berdych 7-6 (7/3) 6-1 in a repeat of his Wimbledon final triumph.
The result meant the Czech, the only debutant at this year's tournament, was eliminated, but there was no disgrace in losing to Nadal on this form.
The Spaniard said: "It was a very important victory because every day I'm playing a little better and today I played a great match. It's going to be a really, really difficult match against Andy."
Berdych had been unable to take the game to Nadal at Wimbledon and succumbed fairly meekly but it was immediately clear he would not make the same mistake today.
Having come into the tournament low on confidence after a miserable run since Wimbledon, the Czech's demeanour changed midway through his victory over Roddick on Wednesday as his ferocious forehand began to fire.
And it was the same Berdych who began today's match by holding serve easily in the opening game and then forcing two immediate break points. Nadal has been in terrific form, though, and two big serves helped him to get out of trouble.
The roles were reversed in the fifth game as a delicious backhand took the Spaniard to 15-40, but this time Berdych dug deep, with a lunging forehand denying Nadal when he looked poised to break.
The Czech was just the sort of player Nadal struggled against early on in his career, and Berdych won three of their first four meetings, but since the last of those in 2006 he had not so much as taken a set from seven further encounters.
The sixth seed's groundstrokes were looking very sharp but his first-serve percentage was down in the 30s, which was giving Nadal a sniff in every game.
Berdych continued to keep the Spaniard at bay, though, and in the 12th game he was two points away from the set at 15-30 on Nadal's serve.
It was a controversial moment. A Berdych backhand appeared to land long and Nadal put his finger in the air to challenge just as the umpire decided to overrule his linesman and call the shot out.
Berdych challenged and the replay showed the ball to be just in. The umpire then awarded the point to the Czech, much to the astonishment of Nadal, who after all had not actually challenged a call, and he debated the point with the umpire and the supervisor.
The decision stood, but adversity is what the Spaniard thrives on and he promptly held to take the set to a tie-break. Indeed, the controversy seemed to affect Berdych more, and he will want to forget most of the 13th game.
Nadal only needed a set to reach the semi-finals at the O2 for the first time, and he greeted the winning forehand with a leap of celebration.
There was still all to play for, though, for Berdych in particular, who had battled away for an hour and 10 minutes in the best set of the tournament for no reward.
He needed at least one set to stay in contention for a last-four spot, so saving a break point in his opening service game of the second set was an absolute must.
He could not repeat that in a lengthy fourth game, however, and an ill-advised drop shot gave Nadal the first break of the match.
That swiftly became two breaks thanks to a sixth double fault from Berdych, leaving the world number one to serve out a supreme victory - even if a between-the-legs winner proved beyond him.
Not surprisingly, the players had differing views of the controversial point in the first set, with Berdych accusing the officials of being intimidated by Nadal.
The Czech said: "It shows that the referee is probably scared of him because he lets him talk with him for too long.
"Every game is very tough. Even if you get a chance to have a 15-30, you need to play, not be waiting and talking for three minutes.
"The rules are quite correct. When you ask for the challenge, he stops the game. It's so simple. He was almost sitting there, like he's not going to play.
"It's not the mistake of Rafa. It's the mistake of the referee. He just needs to show him that it's not like he can do whatever he wants on the court."
Nadal, though, denied he had put his hand up to challenge and insisted the point did not change the outcome of the game, set or match.
"I didn't make a challenge," he said. "He (umpire Carlos Bernardes) called the ball out. Maybe I stopped a little bit because the ball was really close, but I never said stop.
"It didn't change anything, that point. I think I was still playing the same level before that point and after that point."
Anger at that decision aside, Nadal's emotions were a complete contrast from 12 months ago, when he ended a season ravaged by injury with straight-sets defeats by Nikolay Davydenko, Robin Soderling and Novak Djokovic.
Reflecting on his week, he added: "It's a very good end of the season, irrespective of the result tomorrow.
"For me, finishing the season by winning all the matches in the group, three victories against top-eight players on probably the most difficult surface for me, is unbelievable."