The German had to retire injured from a dramatic last-four clash with Rafael Nadal last season after twisting his ankle and did not play again in 2022.

Zverev, who was the third seed last year, is only seeded 22nd this time around after struggling to recapture his best form since returning to the ATP Tour.

But the former US Open finalist had enough to beat South African Harris 7-6 (8/6), 7-6 (7/0), 6-1.

"I was obviously very disappointed with how that tournament ended for me (last year)," Zverev said.

"That's why I think I appreciate even more when I play in a full stadium and the crowd is behind me.

"No (not happy with his performance). But I'm happy that I won in three sets. Normally I start with five-set matches so I'm happy to win in three."

Zverev will next face Slovakia's Alex Molcan as he tries to reach the third round for a sixth straight year.

(For more sports news and updates, follow Ahram Online Sports on Twitter at @AO_Sports and on Facebook at AhramOnlineSports.)