An unstoppable Messi and summer signing Paulinho dictated the rules at San Mames stadium and sent Barcelona three points ahead of Atletico and Real Madrid, with a confident 2-0 win over Athletic Bilbao.
Barcelona continued their impressive unbeaten run - which now stretches to ten games - and left La Catedral once more with all the points thanks to their incredible leader, Messi, who transformed a neat cross from Jordi Alba into Barcelona's ticket to the victory, during the first half.
In the closing moments, Paulinho doubled the scoreline and confirmed the result after profiting from a poor parry by Bilbao keeper Kepa.
Athletic suffered their fifth defeat of the campaign but fought well to counteract the league leaders, with the likes of Aduriz and William pushing forward through the flanks and often threatening ter Stegen's goal.
Barcelona dictated the pace from the first half and saw their first opportunity of the game come from Messi, who, left alone in the box, picked up a rebounded ball and shot a beautiful half-volley which, however, was too central.
Despite Barcelona’s ball possession, Athletic refused to back down, often tried to run through the flanks and had several chances. First, William reached the byline and crossed into the box, finding Aduriz’s head, but the shot lacked power and ten Stegen saved comfortably.
A few seconds later, the away team sleepily let Boveda fool the defence and scuff the ball, only to see it cleared by Sergio Busquets. Aduriz subsequently picked up the ball, passed the centre backs and found himself face to face with ter Stegen, but again failed to find the net.
Twenty minutes in, and Barcelona went very close to scoring again, as Messi, who was left wandering alone inside Bilbao’s box, eased past Kepa but missed an incredible opportunity to score, as his shot hit the post.
Messi's inevitable goal arrived nine minutes before the breaks. The Argentine number 10 profited from a moment of confusion in Athletic Bilbao's defence to pick up a stunning cross from Jordi Alba, and magnificently curled the ball low into the bottom right side of the goal.
It took the away side only two minutes to pose just another threat to Bilbao, as Paulinho, who was on the edge of the box, thumped the ball on the bar. The Basque side poorly tried to equalise before the break, but Barcelona were good enough to hold them back.
Athletic returned from the changing rooms with a renewed thirst for goals and once again the woodwork was tested, this time by the home team, as Raul Garcia's header passed over ter Stegen but slammed the crossbar.
Half an hour before the final whistle, the Blaugrana nearly doubled their advantage thanks to the wonders of Ivan Rakitic, whose magnificent shot from distance forced a brilliant save from Kepa.
Bilbao desperately attempted to give their fans something to cheer and besieged Barcelona's box, with 15 minutes left.
Garcia wasted a good chance when he picked up the ball and had enough time to prepare a shot, which ended up drifting wide.
Atheltic proved to be too tired to put up a fight until the end. During the first minute of added time, a beautiful one-two between lethal duo Suarez and Messi saw the former's shot deflected by Kepa. However, it was picked by Paulinho, who was in the right place at the right time and gently curled it home for Barca's second.
Ernesto Valverde's first return to Bilbao, as Barcelona manager ended in victory thanks to difference makers like Lionel Messi, who he could barely even dream of during his time in the Basque country.