Lionel Messi netted twice in Barcelona's convincing 3-0 victory over Juventus that kicked off their Champions League campaign in style, while Paris Saint-Germain, Manchester United and Chelsea also won big on Tuesday.

After a troubled summer, a home meeting with last season's runners-up may not have been what Barcelona wanted, but Messi was at his brilliant best to give the Catalans the three points.

New signing Ousmane Dembele was handed a first Barcelona start at the Camp Nou but it was Messi who got the opening goal on the stroke of halftime after a brilliant exchange of passes with Luis Suarez.

It was fine play from the Argentine that led to Ivan Rakitic doubling Barca's lead on 56 minutes and Messi saved the best for last with a sublime goal to complete the victory midway through the second half.

"I have suffered many times playing against Messi and now I have the luck to have him on my side," said Barca coach Ernesto Valverde.