ATP World Tour Finals
Venue: O2 Arena, London Dates: 21-28 November
Coverage: One match each day live on BBC TV, streamed online & available through iPlayer; text commentary online and on mobiles for every singles match via BBC Sport website; every singles match live on 5live sports extra.
Highlights - Nadal blows fuse in Berdych win
By Piers Newbery at the O2 Arena
Rafael Nadal took another step towards making up for his disastrous London debut last year by defeating Tomas Berdych to reach the last four at the ATP World Tour Finals.
The world number one failed to win a single set on his first appearance at the O2 but has been a man transformed 12 months on, topping Group A with a perfect record after a 7-6 (7-3) 6-1 win over Berdych.
That Nadal should come through what proved, in the early stages, to be one of the tighter matches of the week was no surprise, but a furious outburst over a line call in the first set was more out of character.
He goes on to face British number one Andy Murray on Saturday for a place in the final in a match that will be shown live on the BBC, and the Spaniard looks in ominous form as he attempts to claim the one significant title that has so far eluded him.
"It's a very important victory. Congratulations to Tomas for the season. I have played every day a little better and today was a great match against a very difficult opponent," Nadal said.
Andy Roddick takes on Novak Djokovic in Friday's late match at 2000 GMT, with the American needing a straight-sets win to overhaul the Serb and make it through to face Roger Federer in the last four.
Nadal could have qualified in certain circumstances with a defeat against Berdych, but he was not about to leave his fate in others' hands and knew that a single set would be enough.
The pair had met 11 times, with Nadal winning eight of those encounters and the last seven in straight sets, including their most recent meeting in the Wimbledon final in July.
That defeat marked the start of a woeful run of form for the Czech that only ended midway through his victory over Roddick on Wednesday, when he finally rediscovered his game to keep his O2 hopes alive.
It just shows the referee is probably scared of him
Tomas Berdych on the hold-up after the controversial challenge
Realistically, they were still hanging by a thread as he was left needing to beat the world number one, but some heavy backhands helped him earn a couple of early break points only for Nadal to see them off with a forehand and an ace.
Nadal looked ready to strike in game five at 15-40 but Berdych responded superbly by firing a forehand winner down the line and following up with a big serve.
Battle was joined and an absorbing set was heading for a tie-break with Nadal serving at 5-6, 15-15, when a Hawkeye overrule prompted a tirade from the Spaniard.
A Berdych backhand was called long but the Czech successfully challenged the call and was awarded the point, enraging Nadal who was convinced that he had managed to return the ball anyway and so should therefore get a replayed point.
"When I returned the ball it went in, so for that there is no discussion," he said. "But he is a great umpire and everybody makes mistakes. I think he did today."
Berdych was convinced that Nadal had in fact tried to challenge by pointing upwards a split second after he hit the ball and before the umpire called it out.
"I didn't make a challenge," responded Nadal. "He called the ball out. Maybe I stopped a little bit because the ball was really close. I did something like this (putting hand up) but I never said 'stop'. To stop the point you have to say 'stop'.
Nadal coy over line call tantrum
"If I don't see the umpire saying 'out' I'm going to continue for sure because it's a big risk for me to say the ball is out."
Nadal was so incensed at the time that he even walked past the umpire's chair to the side of the court and pleaded with tournament supervisor Tom Barnes, but to no avail.
"It just shows the referee is probably scared of him and just let him talk too long," said Berdych."I mean, it's not the mistake of Rafa, it's the mistake of the referee. He just needed to show him that it's not like he can do whatever he wants on the court.
"It was just a normal call so I don't know why he was taking so long."
The decision stood and in the end seemed to benefit Nadal, who celebrated like a man possessed when he won the following point and raced through the subsequent tie-break as Berdych opened with three unforced errors.
That meant Nadal was assured of a semi-final spot and there was still an outside chance for Berdych if he could manage a three-set win, but the pressure continued to build and, facing his third break point of the second set, the Czech played a woeful drop shot to fall 3-1 behind.
His challenge was well and truly over when a double-fault in game six gave up the double-break, and now free of any pressure the world number one almost made a miraculous through-the-legs winner as he closed out the victory after one hour and 54 minutes.