Bilbao separates from relegation zone
Both Thibaut Courtois and Gorka Iraizoz had produced remarkable saves from Markel Susaeta and Emre respectively to keep the scores level at half-time, but the hosts were in front within five minutes of the restart as Mikel San Jose nodded home from Susaeta's corner.
Susaeta then finished the game as a contest with a neat finish from Ander Herrera's through ball 13 minutes from time and Oscar de Marcos rounded off a fine night for the hosts when he stroked home Aritz Aduriz's cross at the end of a flowing counter-attack seven minutes later.
With Barcelona having already won earlier in the day, Atletico knew the pressure was on to keep the gap at the top down to eight points but without the injured Radamel Falcao they never really got going and indeed could have been on the end of an even heavier beating had it not been for some heroics by Courtois.
The Belgian produced his first big save of the night on 22 minutes when he somehow got an outstretched leg to turn Susaeta's side-footed effort from point-blank range behind.
However, despite Athletic dominating possession and territory in the opening period, they nearly went behind moments before the break as Diego Costa knocked down a cross from the right perfectly into the path of the late arriving Emre and the Turk's fiercely-struck volley was brilliantly clawed away by Iraizoz.
Courtois made another fine save from Susaeta at the start of the second period but he only delayed the opening goal for a matter of seconds as from the resulting corner San Jose got above Diego Godin to nod in his fifth goal of the season.
Both keepers were then called into action again as Iraizoz prevented a low drive from Raul Garcia finding the bottom corner and Courtois denied De Marcos from a narrow angle, but the game was becoming increasingly stretched and it was no surprise to see Athletic double their advantage when Ander picked out Susaeta's run through the middle and this time the Spanish international wasn't to be denied as he fired low into the bottom corner.
And Marcelo Bielsa's men rounded off a fine performance perfectly with an excellent team goal six minutes from time as they broke from an Atletic corner and Aduriz's dinked cross to the back post was expertly diverted high into the net by De Marcos.
Defeat means Atletico's lead over Real Madrid in second place is now four points, while Athletic move seven points clear of the relegation zone and up into 12th.