Shapovalov had a walkover into his first Masters final because the second-ranked Nadal pulled out of their semifinal with an abdominal strain.
The odds looked heavily stacked against the 20-year-old Canadian and the top-ranked Djokovic never appeared troubled on his way to a fifth ATP title this year -- putting him level with Dominic Thiem -- and his 77th overall.
"I don't take them for granted like it's something normal or usual or common. I've been blessed to win so many big titles in my life,'' he said. "That's one of the biggest reasons why I'm still playing professional tennis, to fight for these big trophies and to still be able to play the highest level.''
Djokovic served out the match with a love hold, hitting a forehand winner before turning to look at his box and raising his arms in triumph.
"It was my best serving performance of the tournament,'' Djokovic said. "Denis maybe lost his focus a bit.''
Shapovalov entered the match with only one career title -- a modest ATP 250-level tournament in Stockholm last month -- and having lost his three previous encounters against a 16-time Grand Slam winner considered among the all-time greats of tennis.
The big-serving left-hander looked tense, making three unforced errors in his first service game and slipping quickly to 3-0 down against a composed Djokovic playing in his 50th Masters final and 111th overall.
Even though Shapovalov held his next serve, it was inconsistent with a double fault, a mistimed ball toss and an ace. After botching a return on Djokovic's opening serve of the seventh game he whacked his racket into the ground in frustration.
Dropping only four points on his serve in the first set, Djokovic clinched it with another dominant serving game which included two aces and concluded with a volleyed forehand winner at the net.
"It was tough for me to find a groove just because he was really picking his spots on the serve,'' Shapovalov said. "He just places it well, it's tough to read.''
Shapovalov was up against it right from the start of the second set, saving a break point with an ace. Unforced errors resurfaced in the seventh game and Djokovic ruthlessly punished him with a break for a 4-3 lead.
Djokovic saved his first break point of the match at 30-40 in the next game when Shapovalov returned a sliced serve well wide.
With that, the briefest glimmer of hope was gone.
"I'm sure the best things are yet to come for you,'' Djokovic said to Shapovalov during the trophy ceremony.
Djokovic has won every final he's played at Bercy Arena except for last year's against Karen Khachanov, which came after a grueling three-hour semifinal against 20-time Grand Slam champion Roger Federer.
This year, Djokovic did not drop a set and heads to the upcoming ATP Finals in London looking to secure the year-ending No. 1 ranking for a sixth time. That would move him two ahead of Nadal, one ahead of Federer and Jimmy Connors, and into a tie with record-holder Pete Sampras.
Nadal is also in strong contention to finish the year as No. 1 but it remains uncertain whether the injury-hit Spaniard can play at the ATP Finals, which start Nov. 10.
"I'm sad to see that he's injured because that's not what you want to see. I know how that feels,'' said Djokovic, who struggled nearly two years with an elbow injury. "Historically he's had several injuries at the last part of the season, so I hope he can recover. Because without him, obviously the battle for No. 1, but also the tournament itself, is different.''