Read & Watch: Djokovic Continues Quest, Raises His Game In Shanghai
The four-time champion broke down No. 16 seed Isner’s big game in a five-game sequence that propelled him to a 7-5, 6-3 victory over 75 minutes.
Djokovic is now 48-8 on the season and 1,280 points behind Rafael Nadal (9,225) in the 2019 ATP Race To London and the battle for year-end No. 1. The Serbian will now prepare to face sixth-seeded Greek Stefanos Tsitsipas, who is next in line to qualify for the Nitto ATP Finals in November.
Tsitsipas beat Hubert Hurkacz of Poland 7-5, 3-6, 7-6(5) later in the day. The 2018 Next Gen ATP Finals champion has a 1-1 record in his FedEx ATP Head2Head series against Djokovic, who won 6-3, 6-4 in the Mutua Madrid Open final in May. Tsitsipas beat Djokovic 6-3, 6-7(5), 6-3 on hard courts at the Rogers Cup in Toronto last year.
Djokovic was left frustrated by not making an early breakthrough, but consistent groundstroke depth saw him break Isner’s serve to love in the 12th game.
Djokovic won 20 of 25 points from 5-5 in the first set to a 3-0 advantage in the second set and, in losing just five of his first-service points overall (36/41), left Isner with few options to get back into the encounter.
Isner struck nine aces and passed 1,000 aces for the fifth straight season.
"It's always a big challenge returning the serve of Isner," said Djokovic. "He's got one of the biggest serves of all time. He's one of the tallest guys ever to play tennis. Obviously, with that height, the serve is a huge weapon and huge advantage.
"I managed to kind of read his serve and find a good position on the return, at the end of the first set and also [at the] beginning of the second. I won five games in a row, and that was the key, obviously having a break each set, and then I kind of held my serve. I thought it was one of the best serving matches I had lately."
Djokovic, who captured the 76th trophy of his career at the Rakuten Japan Open Tennis Championships (d. Millman) on Sunday, has now won 14 sets in a row. Isner, the Hall of Fame Open titlist (d. Bublik) in July, drops to a 30-17 match record in 2019.