The defender headed home a 93rd-minute free kick to earn the Seleccao victory and consign El Tri to a second consecutive defeat under Miguel Herrera
The defender struck in the third minute of added time, heading home a Joao Moutinho free kick to consign El Tri to a second consecutive defeat, just three days after they had suffered their first under coach Miguel Herrera, against Bosnia-Herzegovina.
Portugal had been once again forced to make do without reigning world player of the year Ronaldo. The Real Madrid star missed the match as he tries to recover from leg injuries in time for Portugal's World Cup opener against Germany on June 16.
Ronaldo is recovering from tendinitis and a muscle injury, both in his left leg. Portugal team-mates Pepe and Raul Meireles were ruled "unfit" for the match, while goalkeeper Rui Patrício also missed action.
Without four potential World Cup starters, Portugal was very patient in its attack early on but were unable to capitalise on scoring opportunities until the final minute of the match.
Meanwhile, Mexico boss Herrera had made headlines when he announced his starting lineup prior to the game, with striker Javier "Chicharito" Hernandez and goalkeeper Guillermo Ochoa on the bench.
But the coach used both players as second-half substitutes. Chicharito made a strong case for why he should start, while Ochoa may have lost his opportunity after allowing the late goal.
Up until that point, Corona had his only real test when Eder received a pass from Fabio Coentrao in the center of the box, forcing the goalkeeper to make a diving save with a left-footed strike in the 22nd minute.
Corona faced a total of two shots on target before Ochoa came on after 45 minutes.
The second half was much more exciting than the first, with the teams going back and forth and sharing scoring opportunities.
Ochoa was called into action in the 50th minute, when Coentrao placed a shot in the lower-left corner off a corner kick. Mexico countered moments later with Andres Guardado barely missing from outside the box.
Chicharito entered the match in the 58th minute for Giovani dos Santos, and the Manchester United man instantly created scoring chances for El Tri.
There was no better opportunity for Mexico than in the 89th minute when Chicharito dished the ball to Alan Pulido in the box for a clear shot, but the Tigres forward had a poor first touch and put it right into the onrushing goalkeeper Eduardo.
His profligacy was punished right at the death when Joao Moutinho delivered a long free kick into the box and Alves nodded the ball past Ochoa.
Portugal were understandably delighted with their late winner but the continued bluntness of their attack means they will no doubt be praying that Ronaldo is fit to play at least some part in their final World Cup warm-up, against Republic of Ireland at New Jersey's MetLife Stadium on Tuesday.