Dembele struck hard, as Barcelona continued their winning run against Athletic Club, after beating Villareal during the week.
Barcelona raced into a 3-0 lead courtesy of an 11-minute that their visitors were unable to deal with. So, the game was actually out of reach in the first half.
Dembele, who was involved in all four goals got the ball in play as he finished off Lewandowski’s cross with a well-taken header into the back of the net.
Pedri’s wide pass found the Frenchman down the right, and he cut inside before firing a curling shot toward the far corner. Simon saved it and parried it wide, where Lewandowski picked up the ball and crossed back into the area, where Dembele rose above Yuri to head into the net.
Six minutes later, Roberto set off over halfway and played a one-two with Dembele. He received e the return ball inside the box and blasted a shot across the face of the goal, which took a deflection off Martinez to wrong-foot Simon and flew into the net.
In the 22nd minute, Dembele gave Yuri another nightmare as he glided past the left-back and inside, towards the box. He passed to Lewandowski in the center, who turned De Marcos with ease and stroked the ball home with his left foot.
In the 73rd minute, Dembele picked up the ball on the right once again, and dribbled forward before playing a beauty of a through ball in behind the defense. Torres raced onto it and fired the ball beyond the onrushing Simon from a tight angle to make it four for Barca.
Despite the brilliance of Dembele throughout, his teammate Sergi Roberto also had a superb game down the right flank, until being forced off with a nasty shoulder injury.
That thumping 4-0 victory sees Barcelona remain second, three points behind Real Madrid, albeit with a superior goal difference of +24 to Los Blancos’ +19.
Bilbao remain sixth, for now, although a third successive game without a win suggests they could soon be sliding down the table.