Alan Shearer is not confident in Manchester United's chances of reaching a first Champions League semi-final in eight years.
United host Barcelona in the pick of the quarter-final ties on Wednesday night before the return leg in Spain six days later.
The Reds made Champions League history in the last-16 by becoming the first team to overturn a two-goal deficit in a knockout tie when playing the second leg away from home.
United's form since that remarkable night in Paris has been patchy at best, though, with Ole Gunnar Solskjaer's men losing three of their last four games.
And Shearer believes United will have their work cut out to get past the five-time European Cup winners.
"You cannot write off Manchester United after the way they fought back to beat Paris Saint-Germain." Shearer says in his Sun column.
"But I just think Barcelona will have too much for them over two games — mainly because of that guy Lionel Messi.
"I expect it will be Messi who makes the difference against United and he is the reason I think Barca will perhaps go on to win the whole thing.
"United and Ole Gunnar Solskjaer deserve this crack against Barca because of what they did in Paris.
"But I just think it will be a step too far for them."
Messi scored his 43rd goal of the season on Saturday night as Barcelona beat Atletico Madrid to virtually wrap up their eighth La Liga title in 11 years.
Ole Gunnar Solskjaer and Mike Phelan were in attendance at the Nou Camp to get a glimpse of what is in store for United this week.
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