An adductor injury is expected to sideline Messi for around three weeks but Barca got the job done without him against Sporting, the club with whom coach Luis Enrique began his playing career.
The other two-thirds of the 'MSN' strike force, Luis Suarez and Neymar, played their part in covering for the absence of Messi with three goals between them.
Suarez got the ball rolling just before the half-hour and Rafinha headed in a second to put the Catalan giants in control.
Alberto Lora's dismissal in the 74th minute made it an uphill struggle for the hosts, with Neymar grabbing his first goal in the 82nd minute and Arda Turan's header making it four two minutes later.
“The final result was deceptive," Luis Enrique admitted after the game.
“It looks easy, but that was not the case. Not at all. The game was not over until [Loro's] red card.
“It is always difficult to win away from home given the dangers which come with it, especially at Sporting, who play with a lot of intensity.
“We were able to create chances and score a couple of goals before the break, but we struggled to get involved in the play in the second half."