The 16-year-old tennis player received a wild card for the ATP 500 in Rio de Janeiro, grabbing a spectacular first round victory.
He is up against his experienced compatriot, Alert Ramos Vinolas, who is 15 years older and 365 places ahead of the rankings.
Alcaras showed the age-envied character of the court and achieved a dramatic 7: 6, 4: 6, 7: 6 victory 3 hours and 36 minutes play.
At no point on the court is it apparent who is the former # 17 with 34 Grand Slam appearances and a 16-year-old debutant on a similar stage.
In the decisive third set, the young man fell behind with 0: 3 games and 0:40 in the fourth, but managed an incredible turn.
The media in his home country are extremely impressed with his game, and they always stop to praise him and the expectations for a glamorous future in the tennis elite.