Jose Antonio Camacho could not inspire his new charges as 10-man Osasuna slipped to another defeat at Sporting Gijon.
Sporting took an early lead through Gonzalez Carmelo, but were pegged back courtesy of Santiago Ezquerro's leveler just three minutes later.
Mate Bilic restored Sporting's lead from the penalty spot after being impeded in the box by Roversio, who was sent off for the foul.
The defeat left Osasuna without a Primera Liga win this season, while Sporting, after back-to-back wins, leapfrogged their opponents out of the relegation zone.
Spirits were high in the Osasuna camp after the appointment of former Spain and Real Madrid boss Camacho earlier in the week, but his reign got off to the worst possible start as his side fell behind after 12 minutes.
Carmelo was the scorer, heading home from close range after getting on the end of Luis Moran's free-kick.
Two minutes later Sporting were handed another free-kick on the edge of the area, but Bilic sent his effort wide of the target.
And within a minute, Osasuna were level.
Oier found Ezquerro inside the 18-yard box and the former Barcelona man finished with his left foot.
The game was in the balance at this stage and Sporting were grateful to their goalkeeper Ivan Cuellar, who denied Oier after 24 minutes.
The defender was set up by Francisco Punal and his header was on target until Cuellar intervened.
Osasuna had another chance when Javier Portillo played Ezquerro through, but he could not find the target.
The game took a decisive turn five minutes before the break, though.
Roversio was penalized for holding Bilic inside the box and given his marching orders.
Bilic took the penalty himself and beat Ricardo to make it 2-1.
With 10 men it became a struggle for Osasuna and Bilic had another chance before the break when he was set up by Moran, but did not trouble Ricardo.
Bilic was in the action again six minutes after the break, firing wide from inside the box.
But the key moment of the second period came 11 minutes after the break when Kike Sola came within inches of drawing Osasuna level.
He headed substitute Masoud Shojaei's free-kick goalwards, but his effort struck a post.
Bilic continued to cause problems at the other end, but was again off target after 68 minutes following good work from Diego Castro.
Masoud tested Cuellar with a direct free-kick 11 minutes from time, but the Sporting stopper was equal to the task.
His Osasuna counterpart was called into action after 88 minutes when Bilic played in Maldonado.
Ricardo saved the ball but the rebound went back to the substitute, who could not direct his second effort goalwards.
