A farewell for Oscar de Marcos had the home support on their feet before kick-off, and they were back up again in the opening minute as Athletic had Barca under immediate pressure.
A brilliant move looked to have brought them the opening goal thanks to Maroan Sannadi’s towering header, but an offside call saw the goal ruled out.
Nico Williams soon went close too, with Barcelona finding it difficult to get out of their own half.
When they did, it was, as so often this season, a result of Pedri’s industry and willingness to get forward. His quick free-kick to Fermin Lopez on 13 minutes caught the Athletic defence cold, and a simple pass allowed Robert Lewandowski to score his 100th Barca goal with a sublime chip.
A few minutes later, the centre-forward wasn’t picked up from a corner and he doubled the lead with a header from close range.
Despite having nothing to play for, the intensity from both teams was a joy to watch, and as the half wore on, Barca exerted more authority with Pedri, Gavi and Lamine Yamal dictating play from midfield.
As the game approached half-time, the visitors were getting time and space to stroke the ball around, and 74% of the ball across the 45 minutes only led to a cacophony of whistles from a disgruntled home support.
Just two minutes after the break, a wonderful ball from Raphinha should’ve seen Lewandowski complete his hat-trick from close range, but his woeful effort ended up in the stands.
Barcelona continued to set the tempo and keep the hosts at arms’ length, with Yamal the next to go close while Lewandowski, again, squandered another chance approaching the hour mark.
When Athletic did manage to get forward, both Williams and Sannadi saw presentable chances come to nothing.
The final 30 minutes took on a familiar feel as Barcelona dominated in all aspects and Athletic had to be content with the occasional foray upfield.
Inaki Pena still had to be saved by the crossbar in the 70th minute after Pau Cubarsi inadvertently headed a cross towards his own goal, though in truth, the visitors were rarely troubled.
Barça added gloss to the scoreline with a 94th-minute penalty from Dani Olmo, which put the seal on their 28th league win of the campaign.
Hansi Flick’s men have lost just once in La Liga in 19 outings since the turn of the year, while Athletic have now failed to win any of the last 11 league H2Hs.
Flashscore Man of the Match: Robert Lewandowski (Barcelona)
Check out all of the match stats here.
