The 35-year-old Spaniard defeated American Denis Kudla in straight sets (6-3, 6-2) and will face another American in the next round, Stefan Kozlov, 103rd in the ATP rankings, who is also his sparring partner.
The world No. 5, broke Kudla, No. 100, in the fourth game of the match to lead 3-1 and move without trembling towards winning the first set.
The favorite also quickly led 4-1 in the second set and then won the match in 1 hour 16 minutes.
Nadal scored eight aces and won 36 of his 40 service points.
Russian Daniil Medvedev after his victory over Frenchman Benoît Paire in the first round of the tournament in Acapulco, Mexico, February 22, 2022 PEDRO PARDO AFP
The Spaniard, who lifted his 21st Grand Slam trophy in Melbourne in January, breaking the record he held with Novak Djokovic and Roger Federer, is seeking a 91st ATP title.
The other man in the epic final in Australia, Russian Daniil Medvedev, obliterated Frenchman Benoît Paire (6-3, 6-4) in the first round in Acapulco in one hour and 41 minutes.
The world number two is able, according to several scenarios established by the ATP, to snatch first place in the rankings from Novak Djokovic on Monday, who is playing for his part in the ATP 500 tournament in Dubai.
The Italian Matteo Berrettini, sixth player in the world, withdrew for fatigue after a first set, however victorious, against the American Tommy Paul.
Frenchman Benoît Paire rips his polo shirt during his defeat against Russian Daniil Medvedev in the first round of the tournament in Acapulco, Mexico, February 22, 2022 PEDRO PARDO AFP
Matteo Berrettini left the court trailing 5-1 in the second set after winning the first (6-4).
© 2022 AFP