The 2009 US Open champion, who made it to the final of the event in Shanghai back in 2013, claimed a 6-2, 3-6, 6-4 at the Qizhong Forest Sports City Arena.

Del Potro, seeded 16th, will take on Andrey Rublev in round two after the Russian beat Damir Džumhur of Bosnia and Herzegovina 6-1, 4-6, 6-1.

Chinese wildcard Di Wu recorded just his second win at Association of Tennis Professionals Masters 1000 level with an impressive victory over Frenchman Jeremy Chardy.

Di progressed to the next round by virtue of a 7-6, 6-2 success against Chardy.

American qualifier Frances Tiafoe, who took Swiss star Roger Federer to five sets at the US Open earlier this year, is also through after he overcame Chardy's compatriot Benoit Paire 6-4, 6-4.

The world number 92 will play either 10th-seeded compatriot Sam Querrey or Yuichi Sugita of Japan.

Chung Hyeon of South Korea claimed the biggest scalp of the day, knocking out ninth-seeded Roberto Bautista Agut of Spain.

The South Korean player put in a superb performance on his way to a 6-4, 6-3 win over the Spaniard, who reached the final in Shanghai last year.

"Today, I was trying to stay calm all the time in the match," said Chung.

"I won today so I did everything good."