Benfica, who already had a 3-1 advantage following the first leg, started off the clash on the front foot, with Eduardo Salvio making an early impact.
After a bursting run, Salvio was able to get past Danny Rose and launch a low cross into the box, which forced Sandro, who was placed at centre-back, to clear the danger.
The first chance of the opening half came for the home side when Luisao, who scored two goals in the first leg, latched on to the end of a header in the box to nudge the ball into the back of the net, but his effort flew over the bar.
Minutes later, the ball fell to Roberto Soldado after a corner was deflected. Despite having plenty of space, the Spaniard unleashed his shot into the ground and wide of the post.
The deadlock was eventually broken, but it caused further damage for Tottenham, as Ezequiel Garay found the end of a cross into the box to head the ball into the back of the net, leaving the match 4-1 on aggregate in their favour at half time.