The 38-year-old Serbian star needed a lengthy medical timeout to treat what looked like a blister on his right foot on Sunday before wrapping up a 6-1, 7-6 (7/3), 6-2 win against his unseeded 19-year-old American opponent on the Arthur Ashe Stadium showcourt.
“Great to be back in New York,” Djokovic said during a brief on-court interview.
“Quite a strange match to be honest. The first set was 20 minutes, the second set was an hour and 20 minutes. It was a key to me to hold my nerve in the second set. All in all, there are positives to take.”
“I wish I had Learner Tien’s age. When you come to the late 30s it’s about learning how to preserve the energy for what matters. I still have the flair, I still have the drive, and you guys give me the energy. Hopefully I can keep it going.”
Djokovic has not played since his defeat in the semi-finals at Wimbledon last month, skipping ATP Masters events in Toronto and Cincinnati to focus all his energy on the US Open.
While there were a few signs of rustiness at times on Sunday, he also laced his performance with flashes of the brilliance that has been his calling card throughout a glittering career.
Djokovic looked to be a man in a hurry in a scorching start, rattling off winners to take the first set 6-1.
Tien, however, was given hope though in a laboured second set performance by Djokovic, but could not convert a break point that would have made it 1-1 when leading 5-4.
Instead, Djokovic held serve to make it 5-5 and reasserted himself to claim the second set tie break, attacking the net cleverly and using some sublime variation to pull Tien all over the court.
Djokovic paused for a medical timeout for treatment to his right foot before the third set got under way.
The rest appeared to give Djokovic a jolt of energy, and he sprinted into a 5-1 lead to leave Tien reeling.
Tien did well to save a match point on Djokovic’s serve before breaking for 5-2.
But the respite was short-lived as Djokovic again responded emphatically, breaking back immediately to wrap up victory.
Djokovic will face US qualifier Zachary Svajda in the second round. (AFP)