Both teams scored deep into stoppage-time as an incredible finish saw Atletico Madrid start the new LaLiga season with a 1-1 draw at home to newly promoted Alaves.
Manu Garcia's stunning equaliser in the fifth minute of stoppage-time cancelled out debutant Kevin Gameiro's penalty, which had itself come three minutes into added time.
Despite wasting a host of chances, Atletico thought they had taken all three points when Gameiro - who had been guilty for several of those poor misses - struck from 12 yards, but the visitors immediately levelled with their first shot on target through a sensational long-range effort.
The away side's sturdy defence frustrated Atletico for much of the match and luck appeared to be on their side when Yannick Carrasco struck the post just before half-time.
Fernando Torres was introduced at the break and he also hit the upright in the second half, before then winning a late penalty, from which Gameiro netted to make amends for his earlier mishaps.
But the valiant visitors somehow found a way to battle back, with Garcia sending a thunderous effort past Jan Oblak from 25 yards to stun Atletico at the death.
Simeone made a point of highlighting Alaves' willingness to absorb pressure in the build-up and they unsurprisingly lived up to that reputation at Vicente Calderon, with Atletico struggling to break them down during the early exchanges.
The hosts quickly resorted to efforts from distance, with Gabi and Gameiro firing just wide in quick succession.
Frustrated Atletico finally crafted a real chance 10 minutes before the break due to the sheer determination of Saul, but the midfielder fired straight at Fernando Pacheco from 18 yards, with centre-backs Alexis and Victor Laguardia putting him under significant pressure.
There was no excuse for Gameiro shortly after, though, as the Frenchman inexplicably blazed over from six yards after Koke's inch-perfect delivery.
As Atletico upped the ante, the post then came to Alaves' rescue just before the break, denying Carrasco from 20 yards after he had been found by Filipe Luis.
Simeone responded at the break by replacing Tiago with Torres in an attempt to overload the Basques and they went close again early on, as Saul nodded Carrasco's scuffed effort just wide from 12 yards.
It continued to prove a frustrating debut for Gameiro, with the striker nodding Filipe's cross away from goal and taking it right off the head of Torres just after the hour mark.
Defender Diego Godin was the next to find himself in a brilliant position, but he prodded over from close range after Carrasco's cut-back.
Atletico's siege continued shortly after, as Torres burst into the left side of the area and smashed a left-footed effort against the near post.
Their patience appeared to pay off when Torres was hauled down by Laguardia in the 93rd minute, with Gameiro finally making his mark and netting from the spot.
But Alaves stunned Atletico in style, as captain Garcia sent a stinging drive past Oblak from distance to secure a point for his side on their return to the top flight.