The left-handed Indian came from behind to beat his Chinese opponent 3-6 7-5 7-6(2) in the opening round, which lasted two hours and one minute.
Divij next faces China's Yan Bai, who shocked second-seeded Australian Luke Saville 6-4 7-6(4).
Karunuday also rallied to beat his rival 6-7 (4) 6-4 6-4 in another gruelling first round match that lasted two hours and 17 minutes.
After taking a set each, the third was locked 5-5 when Divij was broken, allowing Zheng to serve out the match in the next.
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However, Divij not only saved a match point in the 12th game but also broke back his rival to stretch the match to a tie-breaker.
It was one-way traffic in the tie-break with Divij opening up a 4-0 lead, yet again coming on the net to dispatch volleys. From such a healthy lead, it was a matter of time for Divij to close the match.