The Spain international is expected to complete a £22million move to Old Trafford this week after becoming 'angry' at his lack of playing time at the Nou Camp.
Messi scored Barca's first two goals of the evening and was chuffed his long-time team-mate settled the win, despite being in the dark over his future.
"I'm thrilled that Pedro was the one to get the winning goal," Messi said.
AP
Lionel Messi congratulates Pedro after his Super Cup winner
"Personally I don't know what his decision will be but we're all with him and we'll back him.
"We want the best for him given what he's given the club - he deserves the best. I don't know what he'll decide but whatever he'll have our support."
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