Gary Lineker has urged Uefa to abolish the away goals rule next season in a bid to encourage teams to be more adventurous in the first legs of knock-out ties.
Manchester United approached their game against Barcelona on Wednesday night in a pragmatic manner and failed to test Marc-Andre ter Stegen throughout the encounter.
United's defeat, sealed by a first-half Luke Shaw own-goal, means they must next week go to Catalonia and win to stay in the competition.
Lineker suggested United might not have been so cautious had the away goals rule not been in play.
“I don't know about you but I'd love to see an experiment for one season where they get rid of the away goal rule,” Lineker said on BT Sport.
“I just think home legs, first legs, I just think everyone is a little bit cautious.
“They've got a fear of giving away an away goal or two and, if you get an away goal it's like, 'woah, that's it'.”
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Owen Hargreaves responded: “You're right. Barcelona scored an away goal and then sat off.
“The good thing for United is they lost the first game against Paris-Saint Germain 2-0 so they've been there and done it.
“They can find a way but you just expect Barca to play better in that second leg.”
United benefited from the away goals rule in the previous round as they progressed against Paris Saint-Germain despite drawing 3-3 on aggregate.
PSG won 2-0 at Old Trafford on 12 February before United's dramatic 3-1 victory at the Parc des Princes on 6 March.
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