Mexico Open: Novak Djokovic battles into Acapulco quarter-finals with win over Juan Martin del Potro

The Serbian star led a parade of the top four seeds into the last eight, with second-seeded Rafael Nadal, number three Marin Cilic and fourth-seeded defending champion Dominic Thiem all advancing.

Top-seeded Djokovic, back in action this week for the first time since his shock second-round exit at the Australian Open in January, had to dig deep against former US Open champion del Potro after falling a break down in the third set.

He broke back immediately to level the set at 4-4 then held at love to pile the pressure on del Potro, who fended off one match point with a service winner but couldn`t hold off Djokovic on the next.

The Serbian advanced to a quarter-final clash with Australia`s Nick Kyrgios, a 6-2, 6-4 winner over American Donald Young.

Djokovic`s travails in a match lasting two hours and 38 minutes were a far cry from Nadal`s comprehensive 6-1, 6-1 victory over Paolo Lorenzi.

"I played a complete match today and I`m feeling great after a month without playing," said Nadal, a two-time winner in Acapulco who is playing his first tournament since falling to Roger Federer in the Australian Open final.

"I think I played a very solid match ... some great shots, some good winners," added the Spaniard, who dropped just seven points on his serve and never faced a break point against the 38th-ranked Italian.

Nadal broke Lorenzi for the fifth time in the final game of the match, delivering a stinging forehand winner to wrap up the win in just 66 minutes.

Nadal next faces Japanese qualifier Yoshihito Nishioka, a 6-4, 3-6, 6-0 winner over Australian lucky loser Jordan Thompson.

Cilic booked his quarter-final berth with a 6-3, 2-6, 6-3 victory over fellow Croatian Borna Coric.

Cilic, the 2014 US Open champion, remained unbeaten against his 20-year-old compatriot.

He fired a dozen aces, and broke Coric three times in the match, including twice in the final set to set up a clash with American Steve Johnson, a 7-6 (7/5), 6-3 winner over American wildcard Ernesto Escobedo.

Austria`s Thiem advanced with a 7-5, 6-3 victory over Adrian Mannarino.

Thiem, winner at Rio de Janeiro last week, booked a meeting with American Sam Querrey, who toppled fifth-seeded Belgian David Goffin 6-2, 6-3.