The world number two saw off his 20-year-old opponent 6-2 7-5 in one hour and 35 minutes to set up a last-eight clash with Kwon Soon-woo, who stunned eighth seed Dusan Lajovic 7-6 (7-2) 6-0.

Nadal won the first five games of his match and after failing to serve out the set, immediately broke back to secure the opener.

The second set remained on serve until the eighth game, when Nadal took his second break point.

Kecmanovic, the world number 50, broke back but the 19-time grand slam champion stepped it up in the final game to break again and secure victory.

Earlier, second seed Alexander Zverev was stunned by American qualifier Tommy Paul.

The world number 66 won 6-3 6-4.

Grigor Dimitrov beat Adrian Mannarino in a final-set tie-break while Britain's Kyle Edmund saw off fourth seed Feliz Auger-Aliassime 6-4 6-4.

American duo John Isner and Taylor Fritz were also second-round winners in Acapulco while Stan Wawrinka beat Spain's Pedro Martinez 6-4 6-4.

Australian Associated Press