Philippe Coutinho believes it's "difficult to explain" how Barcelona have only won one of the last five Champions League titles with Lionel Messi in their side.
The Catalan's begin their European campaign against PSV Eindhoven in Group B on Tuesday, aiming to win the competition that has alluded them since 2015, when they beat Juventus 3-1 in the final match in Berlin.
Real Madrid have dominated the competition in recent years, winning four of the last five finals, leaving Coutinho perplexed at how a side containing Messi has gone so long without lifting the famous trophy.
As quoted by SPORT, he said: "It's difficult [to explain]. He is the best player in the world, [the best] in the history of the game. It's difficult to explain it.
"Messi, like all of us, is really motivated to win big things [this season] and the Champions League is one of them."
The diminutive Argentine has already claimed four Champions League titles in his illustrious career in 2006, 2009, 2011 and most recently in 2015, although the club have failed to make it past the quarter final stage in four of the last five years.
Barcelona have started the current season well, winning all four of their La Liga games to sit top of the table, with Messi the league's top scorer with four goals, while Coutinho has a goal and an assist to his name.
The Brazilian, who was ineligible for the club in last season's competition having already appeared for Liverpool, believes the club need no extra motivation to win this year due to the prestige of the competition.
He continued, stating: "Motivation to win the Champions League is always really high, for every teams that takes part, because of the grandeur of the tournament."