For forty-five minutes San Mames simmered. Then, in the space of two breathless minutes after the interval, it erupted. Athletic Club, level with nothing but ambition at the break, returned from the tunnel and dismantled Atletico Madrid with a ferocity that left the visitors reeling and their supporters silenced.

By the time Oihan Sancet applied the finishing flourish deep into stoppage time, the scoreboard read 3-0 and the story of the afternoon was long since told. This was not a smash-and-grab or a fortunate ambush. It was a performance of controlled aggression, the kind that turns a solid start to a season into something that feels like a springboard.

Atletico arrived in the Basque Country a place above their hosts and unbeaten in their last outing, but they left flattened, outrun and outfought. The gap in the table was slim; the gap on the pitch, for one afternoon at least, was a chasm.

Two-minute blitz

The decisive passage came the moment the second half began. Barely a minute after the restart, Nico Williams rose in the centre of the box and thumped a header into the middle of the goal. There was a pause, a VAR review, a held breath around the stadium, and then the roar as the goal was confirmed. Athletic had the lead they had threatened before the break.

They did not wait long to double it. Two minutes later Inaki Williams turned defence into attack in the blink of an eye, breaking clear on the counter and squaring for Robert Navarro. The finish was cold and clinical, a left-footed strike planted into the bottom left corner. Two goals, two minutes, and Atletico were shell-shocked before they had even settled.

The brothers Williams were at the heart of it, one scoring, the other supplying, their pace and menace a torment down the flanks. Atletico had no answer to the speed of transition, no way of stemming a tide that arrived without warning and refused to recede.

Atletico undone

For Atletico Madrid this was a chastening afternoon, a reminder that a promising early-season position counts for little without the resilience to protect it. Having taken seven points from their opening four fixtures, they came to San Mames sixth and looking to consolidate. Instead they were exposed, their defence pulled apart by movement they could not track and speed they could not match.

The manner of the collapse will trouble them most. Conceding twice within three minutes of the restart speaks of a side caught cold, undone tactically and mentally at the very moment concentration mattered. Their goal difference, already fragile, took a battering; six goals conceded across the campaign is not the platform of a team with grand designs.

There was no way back once the second went in. Atletico chased the game without conviction, their afternoon defined by the two moments of chaos they could not prevent and never recovered from.

Sancet seals it

If the first two goals were about lightning, the third was about the settled certainty of a job well done. On ninety minutes Oihan Sancet arrived in the box and swept a right-footed shot into the bottom right corner, a strike that carried the calm of a team entirely at ease with its superiority. It was the final, emphatic word.

The San Mames faithful had been waiting for a performance to believe in, and here it was delivered in full. Athletic had lost twice already in a stuttering start, and there was a hunger in the way they played that suggested a team determined to make amends. Every tackle, every surge forward, every roar from the stands fed the momentum.

Sancet's goal turned a comfortable win into a rout, the sort of scoreline that lingers in the memory and the mind. For a side searching for rhythm, three goals and a clean sheet against opposition of Atletico's standing is the kind of afternoon that can define the weeks that follow.

What comes next

Victory lifts Athletic Club to six points and seventh in La Liga, their record now two wins and two defeats, the goals for and against columns tidied into something far healthier. More than the points, it is the manner of the win that matters. A team that had leaked five goals in four games kept a clean sheet and scored three, and did so against a side that started the day above them.

For Atletico Madrid, the reckoning begins now. Still sixth on seven points, they remain in the pack, but the sheen has come off an encouraging opening. A defeat of this scale, so one-sided and so swiftly delivered, demands a response before doubts take root.

The margins in the table remain fine, the season still young enough for narratives to shift week by week. But San Mames witnessed something worth remembering: a home side finding its identity in ninety minutes, and a visiting side losing its footing when it mattered most. Athletic will travel with belief restored; Atletico must rebuild theirs from the wreckage of a Saturday to forget.