LIONEL MESSI and Andre Gomes bagged doubles while Javier Mascherano scored his first goal in SEVEN years as Barcelona cruised to victory at the Nou Camp.
Just three nights after their El Clasico heroics, Luis Enrique’s side routed La Liga’s bottom-placed team with ease.
Messi bagged his 501st Barca goal 12 minutes in before Andre Gomes added a second in the 30th minute.
The only bright spark for the visitors was Roberto Torres’ stunning free-kick which made it 2-1.
But then the floodgates opened with Gomes and Messi’s second goals, Paco Alcacer’s first and Mascherano’s thunderous penalty ending the game in a rampant 11-minute second-half spell.
Alcacer rounded Osasuna keeper Salvatore Sirigu late on to get his second of the night five minutes from time.
A huge “Thanks Leo” banner was raised before kick-off at the Camp Nou, whilst many fans imitated Messi’s goal celebration by raising Barca shirts with Messi’s name on the back in the 10th minute.
The five-time World Player of the Year responded by opening the scoring two minutes later as he pounced on an error in the Osasuna defence to stroll through on goal and lift the ball over the advancing Salvatore Sirigu.
Gomes has been the scapegoat for many of Barca’s most disappointing defeats this season.
But the Portuguese had arguably his best night in a Barca shirt as he drilled home Ivan Rakitic’s cross to make it 2-0 on the half hour.
Marc-Andre ter Stegen was Barca’s other hero from the weekend with a string of stunning saves.
However, the German international was caught out by Torres’s free-kick which brought Osasuna back into the game three minutes into the second half.
Barca, though, simply went through the gears with a four-goal burst in 10 devastating minutes.
Firstly, Gomes slotted home his second of the night after Gerard Pique's initial effort came back off the post.
Messi then curled in his 49th goal in 47 appearances this season from the edge of the area.
And the Argentine instantly made way for 19-year-old Carles Alena to keep him fresh for Saturday's Catalan derby at Espanyol.
Alcacer then finished on the stretch for Barca's fifth.
And when Denis Suarez was felled in the area seconds later the cry went round the Camp Nou for Mascherano to take the spot-kick.
Rakitic obliged by stepping aside to let the Argentine take it and he smashed the ball into the roof of the net for his first goal in 319 Barca appearances.
Alcacer rounded off the scoring four minutes from time when he latched onto Suarez's fine through ball to round Sirigu and slot into an empty net.