The 24-time Grand Slam champion needed just one win or a defeat for young rival Carlos Alcaraz in order to secure top spot in the ATP rankings for 2023 and made no mistake in the Green Group clash with spirited debutant Rune.
Djokovic, on a run of 19 straight wins, has had an age-defying year, winning three Slams to become the all-time record winner of major titles.
The 36-year-old came into the Finals in Turin off the back of his seventh triumph at the Paris Masters, his 40th victory at a Masters 100 event.
Those are two more records to add to a long and growing list for Djokovic, who is hunting a seventh Finals title which would take him one ahead of retired great Roger Federer.
On Monday, Alcaraz makes his ATP Finals debut in the Red Group against Alexander Zverev, the second seed Djokovic's closest challenger.
However, the Wimbledon champion is in uncertain form after being dumped out of the Paris Masters by Russian qualifier Roman Safiullin following his return from an injury lay-off.
The Spaniard hadn't played since the Shanghai Masters in early October due to lower back and left foot problems.
