The Tottenham midfielder stepped up when needed and led Mexico to an important win over the African nation.
It took a full half before coach Luis Fernando Tena decided to play Giovani dos Santos, but it was better late than never as the Tottenham midfielder guided Mexico to a 2-0 win over Gabon in Olympic Group B action at City of Coventry Stadium.
Dos Santos scored El Tri's only goals of the tournament so far with a beautiful left-footed strike off an assist from Oribe Peralta early in the second half and a penalty kick in injury time.
Dos Santos entered the game at halftime after finding himself on Tena's bench for the second straight game despite being a regular starter on El Tri's senior team. The 23-year-old had joined the team late after returning from vacation following the Premier League season.
"He has been doing morning and afternoon sessions with the physical trainers and if he keeps this pace and keeps improving himself he'll get a chance [to start]," Tena said, indicating that Dos Santos may be out of the lineup again when the team faces Switzerland on Wednesday.
Mexico, which began its medal run with a disappointing draw against South Korea on Thursday, now sits nicely in the standings after all four teams drew during the first match day thanks to the super-sub. The top two teams from each group advance to the quarterfinals.
Playing in front of senior team coach José Manuel "Chepo" de la Torre, Mexico was unable to get one past the impressive goalkeeping of Didier Ovono, who had four saves in the first half.
Ovono would get even more action his way early in the second half as Mexico came out of the locker room with a sense of urgency after Dos Santos replaced Miguel Ponce in the lineup. After watching Ovono shut down Peralta with a diving save in the 51st minute, Dos Santos sprung into action.
With his team establishing control in the midfield, Dos Santos took advantage of a golden opportunity set up by Peralta, who handled a long pass and dished the ball to Dos Santos for the shot.
It appeared Mexico had slowed up after Santos' strike, with Gabon going close on several occassions. But all hope for the African nation ended after defender Henri Ndong received a red card for taking down Peralta from behind in the box about a minute into penalty time.
Dos Santos calmly stepped up and beat Ovono on the spot kick despite the goalkeeper guessing the right direction.
"Having Giovani from the bench is a luxury to have," said Tena after the game. "He has proved that he has gotten better physically speaking and he has proved well in this competition coming from the bench."