The Mexican winger pounced on a missed clearance by Federico Dimarco to fire into the net moments after kick-off.
Clocked at 8.95 seconds, it was the third-fastest goal in Serie A history after Rafael Leao's strike for AC Milan against Sassuolo in 2020 (6.8 seconds) and former Piacenza striker Paolo Poggi's goal versus Fiorentina in 2001 (8.9).
However, Napoli could not make their early advantage count and Dimarco made up for his earlier error by tucking in a Davide Faraoni cross to equalise in the 34th minute.
Verona completed the turnaround with an Antonin Barak strike after 62 minutes and Mattia Zaccagni header 11 minutes from time to secure a victory that compounded Napoli's misery following their midweek Italian Super Cup defeat by Juventus.
Napoli are sixth with 34 points from 18 matches, nine behind league leaders AC Milan but with a game in hand, while Verona are 10th on 30 points from 19 matches.