Novak Djokovic started his quest for a record-equalling sixth Nitto ATP Finals crown on Sunday, firing a warning shot to his rivals when he beat Italian debutant Matteo Berrettini 6-2, 6-1 over 64 minutes in the Group Bjorn Borg opener.

Djokovic is now 440 points behind Rafael Nadal in the battle to become year-end No. 1 in the ATP Rankings. The Serbian must reach the final for a chance to be year-end No. 1 for a sixth time, which would match the record of Pete Sampras (1993-98). Nadal begins his campaign on Monday against defending champion Alexander Zverev in Group Andre Agassi on Monday night.

The 32-year-old Djokovic has compiled a 54-9 match record this year, including five tour-level titles at the Australian Open (d. Nadal) and Wimbledon (d. Federer), two ATP Masters 1000 events at the Mutua Madrid Open (d. Tsitsipas) and at the recent Rolex Paris Masters (d. Shapovalov), plus one ATP 500-level title at the Rakuten Japan Open Tennis Championships (d. Millman).

Djokovic made the breakthrough in the sixth game, when Berrettini over-hit two groundstrokes to put him under pressure. While the eighth seed saved the first break point, a forehand in the net handed Djokovic a 4-2 lead. Twelve forehand unforced errors in the 28-minute opener cost Berrettini, the first Italian to play singles at the season finale since Corrado Barazzutti in 1978.

From 2-2 in the first set, Djokovic ran through the next eight games for a commanding 4-0 lead in the second set. A double fault from Berrettini gave Djokovic his third service break, but Berrettini was able to gain a single break for 1-4, when Djokovic struck a backhand wide. Djokovic completed victory with a routine forehand winner, close to the net. The 2008, 2012-15 champion is now 36-12 lifetime at the season finale. Berrettini committed 28 unforced errors in total.

Berrettini, who started 2019 outside of the Top 50 in the ATP Rankings, has enjoyed a breakthrough year and compiled a 42-22 match record. He has won two ATP Tour titles at the Hungarian Open in Budapest (d. Krajinovic) and at the MerdedesCup in Stuttgart (d. Auger-Aliassime). He was also runner-up at the BMW Open by FWU (l. to Garin).

“I think he was returning unbelievable, the most impressive thing that he did,” said Berrettini, who admitted to nerves. “I’ve learned a lot from Roger and from Rafa. For sure I’m going to learn a lot from him. We were playing flat, fast, and he was moving better than me, was playing better than me. So it was tough to win the points. But I think I played really good. I mean, not really good, but a good match. I’m feeling pretty confident.”