The Madrid side defeated Valencia 4-2 in their first leg at Vicente Calderon while Sporting Lisbon came from behind to claim a 2-1 victory over Athletic Bilbao.

Three second-half goals gave Atletico a commanding position after the visitors drew level late in the first half, but a late header from Ricardo Costa handed Valencia a precious second away goal, making the return match at Mestalla a less daunting task.

The opening goal came after 18 minutes when Radamel Falcao found the net with a simple header from close range after Adil Rami could not stop Arda Turan, who beat the France defender at the by-line with his pace.

With the match appearing to head into the break at 1-0, Valencia struck somewhat against the run of play. From a corner Rami made contact, heading the ball down to the far post, where Jonas pounced to tap it in.

The home side enjoyed a superb start to the second half.

In the 48th minute, poor defending saw a free kick from Diego find Miranda inside the heart of the box, where the Brazilian headed past Alves with a simple header.

It took just six minutes for Atletic's third. Adrian took the ball from Mehmet Topal, flew past Victor Ruiz at the edge of the area before firing into the left side of the net, bagging his seventh goal of the competition.

Atletico Madrid eventually grabbed goal number four on 77 minutes after a fine solo effort from Falcao. The former Porto man dribbled past Ruiz and Jeremy Mathieu at the corner of the box, before cutting inside and drilling the ball into the upper-right corner.

Yet Atletico were to be deflated due to the concession of a late goal. In injury time Ricardo Costa headed home a late cross inside the box in added time, and put a different complexion on the second leg next week.

In Lisbon, Jon Aurtenetxe put Bilbao ahead just after the break, but Emiliano Insua got his side level, before Diego Capel completed the turnaround with a fine shot from outside the area.

After a goal-less first half, Sporting came out from the break in pursuit of the opener. Pereira sent in a cross from the right which appeared to strike Fernando Amorebieta on the arm, only for the referee to wave away frantic Portuguese appeals.

The decision proved to be decisive. Seconds later, a Susaeta free kick took an unlucky deflection off Insua into Aurtenetxe's path, and the 20-year-old kept his cool to tuck the ball past Patricio and grab his side a vital away goal.

Soon after, another Susaeta set piece caused mayhem in the Sporting box. Anderson Polga sent a poor clearance into straight to Amorebieta, who drove a shot against the woodwork with Patricio stranded.

The miss only served to fire the hosts on. Shortly afterwards, Capel crossed from the right, and a tame clearance fell to Insua who flew into the box ahead of Susaeta and headed the ball into the far corner.

That was just the beginning. Seconds later, Capel collected the ball 20 yards from goal, and sent a piledriver into the bottom corner, past the sprawling Iraizoz.

In the end, however, the Portuguese outfit were made to settle for a one-goal lead, which Bilbao, having netted an away goal, will fancy their chances of overturning in a week's time.