The 35-year-old Spanish left-hander defeated US lucky loser Dennis Kudla 6-3, 6-2 to book a date with another American who advanced in similar fashion, Nadal practice partner Stefan Kozlov, in the last 16.

Nadal won his men's record 21st Grand Slam title at last month's Australian Open, breaking the career mark he had shared with Novak Djokovic and Roger Federer.

World number five Nadal broke 100th-ranked Kudla in the fourth game for a 3-1 lead and held from there to claim the first set of their first career meeting.

When Kudla sent a forehand long to surrender the first break of the second set, Nadal seized a 2-1 lead and held at love to 3-1.

Nadal broke again for a 4-1 edge and held twice more, claiming the victory on a forehand winner after one hour and 16 minutes.

Nadal fired eight aces and won 36 of 40 points on his serve in the dominating outing.

The Spaniard seeks his 91st career ATP title and third of the year, having also won a Slam tuneup tournament at Melbourne.

Russian top seed Daniil Medvedev, the reigning US Open champion whom Nadal rallied to beat in five sets in the Australian Open final, began his Acapulco run with a 6-3, 6-4 victory over Frenchman Benoit Paire.