Atletico Madrid's poor start to the season took another turn for the worse with a defeat at Osasuna which could spell the end for coach Abel Resino.

The visitors were woeful from start to finish with the defence particularly culpable. Lacking organisation and leadership, the back four were vulnerable throughout, especially in the air as Osasuna created chances at will.

Veteran striker Walter Pandiani scored twice with Carlos Aranda also netting inside the opening half hour as the visitors succumbed to their third defeat of the season.

Resino, who spent most of the evening shaking his head and gesticulating from the technical area, must now fear for his future with his expensively-assembled team second best to a side who narrowly avoided the drop last term.

Atletico, without Diego Forlan who was left in the capital after his exertions on international duty last week, were on the back foot from the off and fell behind in just the fourth minute.

Javier Camunas was allowed to turn back on to his favoured right foot and his cross found Pandiani, who stooped to head inside Sergio Asenjo's near post from close range.

Atletico almost equalised seven minutes later when Sergio Aguero was put through on goal. The Argentinian fluffed the opportunity, however, by trying to dribble past home keeper Ricardo, allowing Cesar Azpilicueta to get back and clear.

Pandiani wasted a similar chance shortly afterwards when he too tried to round the keeper only for Asenjo to get a foot to the ball, forcing the Uruguayan to lose control.

The journeyman striker made no mistake after 27 minutes though, heading in after Miguel Flano nodded down Francisco Punal's left-wing free-kick.

It was 3-0 on the half-hour mark despite the best efforts of Asenjo, who was offered no protection at all from those in front of him.

The keeper, back from national team duty at the Under-20 World Cup, did brilliantly to turn away Javad Nekounam's header from another set-piece only for the ball to remain in the danger zone.

Osasuna duly won it back and it found its way to Juanfran, whose shot was again superbly kept out by Asenjo, who looked up to see an unmarked Aranda on hand to tap home.

Atletico ought to have pulled one back before the break but Aguero again missed the target, this time from six yards after he had been picked out by a pin-point cross from Maxi Rodriguez.

There was another let-off for the visitors after 43 minutes when yet more slack defending allowed Aranda a clean run on goal.

Asenjo halted the initial break but the ball fell kindly for Juanfran, who should have done better than loft his right-footed shot over a gaping net.

The second half lacked the goalmouth action of the first with Atletico substitute Raul Garcia, afforded a generous reception by the Osasuna fans on his return to Pamplona, firing wide from 20 yards on the hour mark.

Atletico's defensive frailties appeared once more after 62 minutes when a lofted ball into the box by Juanfran fell at the feet of Aranda but his goalbound shot struck Cleber Santana and flashed wide.

Another punt into the Atletico box caused havoc in the 74th minute. But having let the ball bounce, Luis Perea redeemed himself with a wonderful challenge just as Camunas was about to shoot.

Atletico did at least manage a couple of late efforts but both Jose Reyes and Aguero were denied by Ricardo.

Aguero, the only Atletico player to emerge with any credit, also fired over late on.