Novak Djokovic marked his Shanghai Masters return with a hard-fought straight-sets win over Alex Michelsen. (More Tennis News)
The four-time champion, who is appearing in this event for the first time since 2019, required two tie-breaks before prevailing 7-6 (7-3) 7-6 (11-9) in just under two hours.
Djokovic, still donning a protective sleeve over his right knee, made a slow start in only his second match since losing to Alexei Popyrin in the US Open third round, winning just four points in the first three games as he fell 4-1 behind.
However, the 24-time major winner broke back in the seventh game before dominating the tie-break for first blood.
Roles were reversed in the second set as Michelsen cancelled out an earlier break in game seven.
However, the American squandered two set points to level and was eventually punished by Djokovic, who will play either 28th seed Flavio Cobolli or three-time major winner Stan Wawrinka in the next round.
Data Debrief: Djokovic continues American dominance
Djokovic was given an early scare, but his experience eventually showed as he came through.
Including team events, the Serb has now won his last 33 ATP-level matches against American opponents, with his last such defeat coming against Sam Querrey at Wimbledon in 2016.
The 24-time major winner also demonstrated his determination when the pressure intensified, and he has now come through 12 of his 16 tie-breaks played this season.
