Barcelona began their quest for a sixth Champions League title with an emphatic 7-0 win over Celtic at Camp Nou.
A hat-trick from Lionel Messi, plus goals from Neymar, Andres Iniesta and Luis Suarez's double, gave Luis Enrique's side all three points to banish memories of Saturday's shock LaLiga defeat to Alaves.
Messi rifled in an early opener and he combined superbly with Neymar to double Barca's lead after Moussa Dembele had seen a penalty saved by Marc-Andre ter Stegen.
Neymar bent a free-kick over the wall and beyond Dorus de Vries from 20 yards just after half-time, and the Brazil star set up Iniesta for a sumptuous fourth before the hour mark before Messi completed his treble just a minute later.
Brendan Rodgers' side could scarcely get out of their half as Barca utterly dominated proceedings, and Suarez - a man he described as the world's top player this week - fired in a stunning sixth from Neymar's fourth assist of the match before poking home Messi's cross to cap the win.
The only sour point for Barca could come in the form of UEFA disciplinary action, with the Champions League anthem booed resoundingly by home fans who displayed 'estelada' flags in defiance of warnings from European football's governing body.
Rodgers warned before the match that even "two double-deckers in front of goal" may not be enough to keep Barca quiet, but he will have been furious at the manner in which his side gifted them the lead.
With just three minutes played, Neymar's clever reverse pass on the left sent Messi clean through a static Celtic defence, and he blasted a shot high past De Vries from a tight angle.
6 - Lionel Messi has now scored six hat-tricks in the Champions League, more than any other player in the history of the competition. Tres.-- OptaJoe (@OptaJoe) September 13, 2016
Celtic - who were thrashed 6-1 on their last visit to Camp Nou in 2013 - fashioned a chance for an equaliser when Ter Stegen tripped Dembele inside the area as he ran on to Scott Sinclair's pass, but the forward's stuttered run-up fooled nobody and the Barca keeper palmed away his penalty comfortably.
Dembele's miss was compounded as Barca doubled their lead just three minutes after that reprieve. In stunning style, Messi and Neymar exchanged passes inside a crowded box before the Argentina international prodded in from point-blank range.
Kieran Tierney cleared Ivan Rakitic's volley off the line and De Vries saved well from Neymar on a lightning-fast break from Barca prior to half-time, but a third goal for the home side was beginning to look inevitable.
And it duly arrived less than five minutes after the restart. Messi, fouled on the edge of the area, passed up his first chance for a hat-trick by allowing Neymar to take the free-kick, and the Brazil international picked out the top-left corner for his fourth goal in two home games against the Scottish champions.
4 - Neymar is the first player to assist four goals in a Champions League game since Zlatan Ibrahimovic in November 2012 for PSG. Unselfish.-- OptaJoe (@OptaJoe) September 13, 2016
Iniesta, on as a half-time substitute, got Barca's fourth as he hammered a volley high into the net following Neymar's pinpoint cross, and Messi completed his hat-trick one minute later, turning home from inside the six-yard box after Suarez had cut the ball back into his path.
Suarez had endured a relatively quiet game but he was not to be denied his own moment of magic, chesting down Neymar's clever lofted pass before swivelling and striking high past De Vries from six yards.
Messi saw a low shot tipped onto the post by De Vries but, after the resulting corner was only half-cleared, Iniesta picked out Barca's number 10 with a fine throughball and he in turn set up Suarez to steer home as Barca scored seven goals in a Champions League match for the second time.