Greg Rusedski says Rafael Nadal's depth was too much for Roger Federer to break down in their semi-final match in London.
Nadal eased into the final of the season-ending ATP World Tour Finals after powering past Federer in straight sets 7-5 6-3.
It means the Spaniard booked a place in Monday's final against either Novak Djokovic or Stanislas Wawrinka and Sky Sports expert Greg Rusedski had nothing but admiration for the world number one's performance.
He said: "What a sensational performance from Nadal.
"He really played the big points well today and that was the difference between the two especially early on in that game where Federer had those three break points and couldn't convert, he defended them and when he got his chances he connected every time on break point.
"What was impressive from Nadal was his depth. The forehand was going so much deeper and even the forehand up the line. He just had every shot today and was the better player."
Take the positives
The loss brings a disappointing season for Roger Federer to an end. The 14-time Grand Slam champion has failed to reach a final at any of the major tournaments this year, but Rusedski believes the Swiss man will take positives from his performance at the O2 this week.
"Federer couldn't find a way through Rafa," said Rusedski.
"Federer played as well as I've seen him play throughout these Championships in the first set but still he ends up losing it.
"When he got himself back to 5-5 Rafa still finds that extra gear and that is what happens when you're world number one, won ten titles and done everything that Rafa has done this year - you just have that little bit of extra confidence in matches even though this is Federer's favourite surface.
"It's going to hurt losing to Rafael Nadal but Federer has got to look at the positives; This is the first time he's beaten two top ten players back-to-back and his first set today was the best I've seen him play this season other than maybe at the Australian Open.
"Federer will continue to build in the off-season to get ready for 2014 and Roger will be back and better."
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