Martins left his marker for dead and slotted past Claudio Bravo after Jose Javier Barkero's 70th-minute penalty had cancelled out David Zurutuza's strike in the 23rd minute.
Griezmann and Ballesteros. Photo: EFE
In Valencia, new signing Obafemi Martins was a hero on his debut for Levante when the speedy Nigerian came off the bench to net a scorching 86th-minute winner in a 2-1 comeback win at home to Real Sociedad.
Real Sociedad went in front at Ciutat de Valencia stadium through David Zurutuza's long-range strike off the upright in the 23rd, only for Jose Barkero to level for Levante with a penalty with 20 minutes to play.
Martins, who had gone on after halftime, used his pace to chase down Sergio Ballestero's long pass, head it forward and fire past the goalkeeper to snatch the win in dramatic fashion before celebrating with a series of somersaults.
The former Inter Milan and Newcastle player joined Levante this month on a free transfer from Russia side Rubin Kazan. "Already in my first training session I saw that Levante isn't such a small club as some people think, and I am very happy to be here," the Nigeria international said.