Messi was on the bench for Saturday's defeat to Alaves having missed Argentina's draw with Venezuela, but he was fit enough to come on for the final had an hour.
He's shown no ill-effects since then and is set to start against Celtic in the Champions League on Tuesday night.
“It would be silly to say Leo is not important," the left-back said in a press conference on Monday.
“He gives an added quality to the team, even if the squad has great quality, but Leo makes us better, he helps us in defence.
“He has been at the top level for 12 years, you have to admire that.
“He's been at the top for so long — no one else has managed that."