Novak Djokovic began his attempt to equal Roger Federer's record number of ATP Finals triumphs with a straight-sets 7-6(4), 6-2 win over Casper Ruud on Monday.
World No. 1 Djokovic is looking to complete a remarkable year with a sixth Finals title after only just missing out on claiming all four Grand Slams in a single season, and got off to a strong start against eighth seed Ruud, winning in around 90 minutes.
Djokovic attracted wild applause from the Turin crowd when he insisted on speaking in Italian for his on-court interview after the match, before which he was honoured for once again being the world's top player.
"It's a great feeling being back here in Italy... thanks for all your support over these years, Italy is like a second home for me," Djokovic said.
Sixth-seeded Matteo Berrettini of Italy saw his challenge suffer a painful end when injury forced him to retire against Alexander Zverev.
The results:
Green Group: Novak Djokovic bt Casper Ruud 7-6 (4), 6-2.
Red Group: Alexander Zverev bt Matteo Berrettini 7-6(9), 1-0 (retired) .