Novak Djokovic posts first Tour win since Australian Open in Acapulco opener

Djokovic, a wild-card entrant who is the event's top seed, got past Slovakia's Martin Klizan 6-3 7-6 (4).

The Serbian star didn't serve effectively through most of the match, though Klizan's only two service breaks came in the second set. However, Djokovic had enough to get through the decisive tiebreaker.

Djokovic had been idle since falling in the second round of the Australian Open to Uzbekistan's Denis Istomin in a five-set thriller.

In other first-round matches Tuesday, second-seeded Rafael Nadal defeated Germany's Mischa Zverev 6-4 6-3 in a battle of left-handers. The same pair met earlier this year in Brisbane, Australia, where Nadal also emerged with a win.

Third-seeded Marin Cilic of Croatia needed three sets to get past Ukraine's Alexandr Dolgopolov 6-3 4-6 6-0. Fourth-seeded Dominic Thiem of Austria topped France's Gilles Simon 7-6 (7) 6-3.

Sixth-seeded Nick Kyrgios of Australia also advanced, rebounding to top Israel's Dudi Sela 3-6 6-3 6-3.

Jack Sock, fresh off winning the title in the Delray Beach Open, was bounced in the first round at Acapulco. Japan's Yoshihito Nishioka beat the American 3-6 6-2 6-1.

American Donald Young got a victory when Aussie Bernard Tomic was forced to retire due to the heat after Young won the opening set 7-6 (5). Tomic, however, was back in action Tuesday night for a doubles match, which he and partner Paolo Lorenzi of Italy lost 7-5, 6-2 to American John Isner and Spaniard Feliciano Lopez.