Novak Djokovic has made a winning return in China in his first individual tournament since his shock US Open defeat by Alexei Popyrin - and his Australian conqueror also made comfortable progress at the Shanghai Masters.

In the five weeks since 24-time grand slam champion Djokovic was beaten sensationally by Popyrin in four sets at Flushing Meadows, the great Serb has only played one singles match, turning out for his country at the Davis Cup last month.

But Djokovic, who's not played a regular tour event outside slams and the Olympics since May, looked in decent nick against rising Alex Michelsen to reach the third round on Saturday in his first match in China since 2019.

He proved too strong for the 20-year-old in two tiebreaks, prevailing 7-6 (7-3) 7-6 (11-9).

"I haven't played in a while so it took me a bit of time to get the rust off and get things going but he started off terrifically, big serves and a quite aggressive style of tennis," said Djokovic, admitting he was impressed by the young American.

"It was quite a high level of tennis. I'm just glad to keep my calm when it mattered in the second set tiebreak."

Michelsen, ranked 43 in the world, had begun impressively, racing into a 3-0 lead only for Djokovic to level at 4-4 and then go on to dominate the breaker.

Michelsen mounted the comeback in the next set after Djokovic had forged into a 4-1 lead, with the Serb having to hold off a couple of set-points before sealing victory in five minutes under two hours.

Djokovic had been left hugely impressed by Popyrin's progress in New York too after the Australian took him down in four sets in their third grand slam meeting of the season at the end of August, following the Serb's wins in Melbourne and Wimbledon.

And the 25-year-old Sydneysider is out to make another splash at a Masters 1000 event in Shanghai after claiming the title in the Canadian Open in Montreal, by far the biggest triumph of his career.

Popyrin, the 20th seed, started his quest well enough on Saturday, outplaying Serbian Miomir Kecmanovic 6-3 6-2 at the Qi Zhong Tennis Centre to set up a last-32 meeting with either Bulgarian Grigor Dimitrov, the No.9 seed, or Belgian Zizou Bergs.

It was a day for the big names to make comfortable progress, with No.3 seed Carlos Alcaraz and top seed Jannik Sinner having no trouble shrugging off the quick turnaround following their epic final in Beijing on Wednesday.

Alcaraz, who had prevailed in a classic showdown with the Italian world No.1, defeated China's Shang Juncheng 6-2 6-2 while Sinner beat Japan's Taro Daniel 6-1 6-4.

Alexander Zverev, the No.2 seed, also breezed through, beating Italian qualifier Mattia Bellucci 6-4 6-2.

There was one big casualty, though, with sixth seed Andrey Rublev, the Russian Popyrin beat for his Canadian crown, losing to the 19-year-old Czech NextGen star Jakub Mensik 6-7 (7-9) 6-4 6-3.