Lionel Messi, Luis Suarez and Neymar combined to devastating effect as Barcelona swatted Celtic aside 7-0 at the Nou Camp to lay down a marker in Champions League Group C.
Messi produced a stunning display, hitting a record sixth hat-trick in the competition.
He smashed home a pass from Neymar in the third minute and the Argentine maestro struck again in the 27th after Celtic's Moussa Dembele had a penalty saved by goalkeeper Marc-Andre ter Stegen.
Neymar curled in a free kick to stretch Barca's lead in the 50th minute before crossing for Andres Iniesta to volley the fourth.
Messi then grabbed his third goal, overtaking Real Madrid greats Alfredo Di Stefano and Ferenc Puskas to reach six European Cup trebles.
Neymar laid on the sixth for Suarez and the Uruguayan completed the rout with his second strike in stoppage time.
Barca coach Luis Enrique reverted to an almost full-strength team after his rotation policy backfired in Saturday's shock 2-1 La Liga defeat at home to Alaves.
The hosts quickly asserted themselves as Neymar slid the ball into Messi's path following a short corner and the Argentine took a touch in the area before scoring.
Barca continued to exert early pressure but were almost undone when Ter Stegen tripped visiting striker Scott Sinclair.
Despite scoring a hat-trick against arch-rivals Rangers at the weekend, the 20-year-old Dembele looked short of confidence as he took the penalty and Ter Stegen dived to his right to beat his shot away.
The German international has now saved three out of four penalties in the Champions League for Barca.
Luis Enrique's men showed no mercy with their next attack, Neymar and Messi cutting Celtic's defence to ribbons.
Neymar played a one-two with Messi before cutting the ball back for the Argentine to score.
Neymar got the goal his superb display warranted early in the second half, fizzing a free kick beyond Celtic's helpless goalkeeper Dorus de Vries.
English club Arsenal came back to salvage a 1-all draw at Paris St Germain, while Manchester City's match with German side Borussia Moenchengladbach was postponed due to torrential rain and a sodden pitch in Manchester.