The teenage forward opened his account for the club in Pamplona just five minutes after coming on as a substitute. He got across his marker to head home and make it 1-1, with the game eventually ending 2-2.
Osasuna sealed their promotion to La Liga on Monday with three games to spare after Granada beat Albacete 1-0.
The Navarra side, relegated from the top flight in 2017, lead Spain's second division on 78 points from 39 games and are guaranteed to finish in the top two after third-place Albacete's home defeat left them 10 points adrift.
Osasuna spent 14 seasons in La Liga before being relegated in 2014. They returned to the top flight after winning in the playoffs in 2016, before immediately going...
Osasuna have sacked coach Petar Vasiljevic following his failure to keep the club in La Liga.
The 46-year-old Serbian took up the reins in January, replacing Joaquin Caparros, but could only guide the Pamplona outfit to a 19th-place finish.
A statement from the club on Wednesday afternoon read: "Club Atletico Osasuna has decided to dispense with the services of Petar Vasiljevic, who in the season that has just concluded occupied the positions of sporting director and coach."