World number one Novak Djokovic began his quest for a sixth title at the season-ending ATP Finals with a 7-6, 6-2 victory over Norway’s Casper Ruud in their round-robin encounter in Turin, Italy.

Djokovic suffered a fall and lost his opening service game but recovered to find his rhythm against Ruud, who is making his debut at the event following five tournament wins this season.

Ruud’s powerful forehand helped him keep pace with Djokovic for much of the first set. However, he was outplayed in the tiebreak as the 20-times major winner forced his 22-year-old opponent into a string of errors to take the opener.

It was plain sailing in the second set for the Serbian, who broke in the first game and dominated the longer rallies as Ruud struggled on serve before eventually going down in an hour and 31 minutes.