Atletico Madrid dropped two points in extraordinary fashion after conceding a stoppage-time equaliser to Alaves in a 1-1 draw having only gone in front two minutes earlier.
Coach Diego Simeone had seen Atletico's principal La Liga title rivals Barcelona and Real Madrid win their opening games and it seemed they had finally made the breakthrough when debutant Kevin Gameiro, who had wasted earlier chances, converted from the spot after a penalty was controversially awarded for a foul on Fernando Torres.
Incredibly though, Alaves conjured a leveller when Manu drilled a sweet 25-yard shot beyond Jan Oblak, who had barely had a save to make in a match Atletico dominated.
Atleti's first sight of goal was a brief one as Alaves' Moroccan defender Zou Feddal was quick to block a shot from Koke after Juanfran's cross deflected to him after eight minutes.
Feddal had to come off within two minutes after suffering an injury off the ball, with Victor Laguardia coming on to replace him.
Atletico set up camp in Alaves' half, as Diego Godin headed wide from an 18th-minute corner with Tiago doing likewise minutes later. Gabi volleyed wide after 21 minutes after Raul Garcia only half-cleared Yannick Ferreira Carrasco's low centre.
Saul Niguez took too long to pull the trigger when a chance came his way in the 35th minute and then Gameiro, signed from Sevilla in the summer, missed a sitter as he fired over Koke's cross from close range.
A penalty shout was waved away after Tiago went down as he challenged Daniel Torres for the ball, and Carrasco was unlucky as his curling 43rd-minute shot from the edge of the area beat Fernando Pacheco but clipped the outside of the post.
Fernando Torres replaced Tiago at the break as Simeone tried to inject more dynamism to his side. Left-back Filipe Luis was off-target with Atleti's first sight of goal in the second period and Saul was unable to direct a header on goal from Carrasco's dangerous ball in after a short corner routine caught Alaves napping.
Pacheco made a smart save to tip over Godin's far-post header in the 57th minute as Atletico continued to press.
The frustration mounted as Godin somehow stabbed over from six yards after Torres found him in space following a twisting run which pulled the Alaves defenders out of position.
The former Liverpool and Chelsea forward then smashed a left-foot shot against the near post when his best option appeared to be to shoot across Pacheco towards the far post, and fluffed a headed chance when he got goalside of Laguardia.
Alaves were scrambling to get bodies in the way of every effort as the hosts' search for a goal became ever more desperate.
Gameiro again seemed certain to score after 85 minutes when Godin headed a corner down into his path, but he was twice denied at point-blank range by Pacheco as two points slipped away from the hosts.
That looked to be the last chance, but as the game ticked into injury time the real drama began.
Gameiro kept his cool to score from the spot after Laguardia was judged to have wrestled Torres to the ground in the box, but the stadium was silenced by Manu's moment of magic in the final seconds.