Trailing 2-1 in the tie, Ernesto Valverde handed a start to Messi and he played a part in both of Dembele's goals before making sure of the aggregate victory by finding the net himself just after the break.

However, Levante president Quico Catalan had already said his club will challenge Barcelona's progression, with reports in Spain suggesting the LaLiga champions fielded an ineligible player in the previous meeting.

Defender Chumi featured in that game, even though he had been due to serve a suspension after picking up five bookings in the Segunda Division B, and Catalan told reporters prior to kick-off that Levante would lodge an official complaint to the Royal Spanish Football Federation.

The selection of Messi, who did not feature in the first leg, was an indication of Barcelona's intent to progress, and the Argentinian twice came close to scoring in the opening 25 minutes, with goalkeeper Aitor Fernandez parrying away a free-kick before diverting another try wide with his foot.

Yet Barca soon went ahead on aggregate as Dembele benefitted from two moments of good fortune to score twice in as many minutes.

First, the ball looped up off the Frenchman and went in following Erick Cabaco's desperate slide tackle, before Dembele's weak finish from a tight angle was helped in by Fernandez's foot to make it 2-0.

Messi was then played in by Dembele only to see his effort from point-blank range denied by Fernandez, the keeper then thwarting Philippe Coutinho and Messi again before the break.

Barca's aggregate lead was only a solitary goal until Messi finally got on the scoresheet nine minutes into the second half.

Dembele was involved as he threaded a superb pass through to Nelson Semedo, who squared the ball for Messi to slot past Fernandez for the home side's third.

A hat-trick alluded Dembele, though, as he fired just wide late on, while the woodwork denied Emmanuel Boateng scoring for Levante in stoppage time.