Roger Federer gained sweet revenge over Novak Djokovic for his Wimbledon final defeat in their winner-takes-all clash at the ATP Finals at London's O2 Arena on Thursday night.
Djokovic knew he had to win the title in order to have any chance of overhauling Rafael Nadal at the top of the rankings and equal Pete Sampras' feat of finishing a year ranked No 1 on six occasions.
But he was denied progress by a majestic display from Federer, who won the straight shoot-out 6-4 6-3 to join Group Bjorn Borg winner Dominic Thiem in the semi-finals of the season-ending tournament. He will now have his sights set on winning a record-extending seventh end-of-season title and first since 2011.
The duo faced each other for the 49th time and first since Djokovic's epic Wimbledon final victory in July. The O2 Arena was bubbling with excitement at this mouth-watering encounter and they were not to be disappointed.
Djokovic started poorly with three double faults in his opening two service games costing him as Federer marched into a 3-1 lead.
The 38-year-old Swiss was purring with confidence, strutting his stuff around the court, while his supporters lapped it up. It was a serving masterclass from Federer, who dropped just three points on serve and made just one unforced error to wrap up the opener.
While Federer was trying to avoid only his second group stage exit in 17 appearances at the year-ending showpiece, the stakes were even higher for Djokovic. He was forced to battle back from 15-40 down to hold serve at the start of the second set.
The Serb was grimacing in pain after a rally in the second game, holding his right elbow when stretching for a ball. But he kept a brave face as he maintained his aggression to try and keep a rampant Federer at bay.
However, after the 20-time Grand Slam champion saved two break-points to hold in the fourth game, he broke through in the next and he soon completed a magnificent win in 73 minutes by breaking to love.
Stats of the match
Federer advances to the semi-finals of the ATP Finals for the 16th time in 17 appearances. He also breaks a five-match losing streak against Djokovic.
Rafael Nadal is guaranteed to finish No 1 in the ATP rankings for the fifth time.
Federer: I played incredibly well
Djokovic: Roger deserved to win
What's next...
Federer could now face a blockbuster semi-final against world No 1 Rafael Nadal should the Spaniard defeat Stefanos Tsitsipas and hope Daniil Medvedev can beat Alexander Zverev in their final round-robin group match on Friday.
Thiem will play the runner-up in the Group Andre Agassi, which could end up being either Tsitsipas, Zverev or Medvedev.
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