Federer through to last four
Roger Federer defeated David Ferrer for the 14th successive time to book his place in the semi-finals of the ATP World Tour Finals in London.
The second seed, and defending champion, still has a final Group B match to come against Juan Martin Del Potro on Saturday but Thursday's 6-4 7-6 (7/5) victory was his second straight-sets win of the tournament and means he cannot be denied a spot in the last four.
Ferrer went into the clash on an 11-match winning streak but he had managed only three sets in his previous meetings with Federer compared to 27 for his opponent and again came out second best.
Federer is looking for his third straight title at the O2 Arena and he made a great start this afternoon, winning the first three games.
That did not tell the whole story, though, as he fought off six break points, and they were back level after Ferrer finally took his eighth chance.
The 30-year-old Spaniard has had the season of his life, winning more titles and more matches than anyone else on the ATP Tour.
He was pushing Federer, who was making quite a few errors but, as he so often does, the world number two found another gear when he needed it to break to love and secure the opening set.
Ferrer had another opening at the start of the second set but could not take it, Federer saving two more break points.
The set was very tight and Ferrer stayed with his opponent all the way until the tie-break, but an error on the sixth point proved crucial.
Federer had been immaculate on serve and took his third match point when a Ferrer return dropped long to become the first singles player through to the semis.
While an advantage in the head-to-head record obviously helped his confidence, Federer admitted to feeling the pressure of trying to maintain such a long streak.
The 31-year-old also recalled the first tournament at the O2 in 2009, when Nikolay Davydenko ended a 12-match losing streak against him in the semi-finals and went on to win the title.
Federer said: "Streaks have ended for me at the World Tour Finals. There was Davydenko and (Fernando) Gonzalez as well years ago when he beat me for the first time.
"In some ways it's helpful to have that one-sided head-to-head record, but at the same time it sometimes creates pressure as well. You always feel like this next match it is probably going to happen.
"You try hard, he tries harder, too, because all he needs is that one win, so then he's got that. I tried hard to not make it happen today. You could feel that he's confident, he's on a run. I think it's a great victory for me."
Ferrer felt he missed his opportunity to pile pressure on Federer at the start of the match when the Swiss star was not serving well and seven break points went begging.
The fourth seed said: "I had a lot of chances to break him but I couldn't do it. When he has one break point on my serve, he makes it.
"Sometimes with these players, if I don't take my chance, I don't win the important points. It is very difficult to win these matches."
Ferrer will still have a good chance to reach the semi-finals if he beats Janko Tipsarevic in his final round-robin match on Saturday, and if he then makes the final he will overtake injured compatriot Rafael Nadal to become world number four.
Ferrer played down the significance, though, saying: "I don't think about that because Rafa is injured. I don't care if I finish four or five in the world.
"I am trying to do my best to have a great tournament here. Then next week I will have a very important Davis Cup final."
Federer, meanwhile, revealed his surprise that the ATP board have reportedly turned down a proposed increase in prize money at the Masters 1000 tournament in Indian Wells next spring.
The ATP Player Council president said: "I will investigate and make sure that the decision they've taken is, indeed, the right one. If it's not, then obviously we need to talk about it, what we can do in the future. It's an important issue here."