Yet Chelsea's elder statesmen - almost certainly featuring together in a Champions League campaign for the last time - are refusing to be cowed by Messi and Barcelona's reputation as one of the best teams of all time.
"From the start of every game, it's 50-50," Chelsea veteran Frank Lampard said.
"We are in the Champions League semi-final on merit. We can't show too much fear against them. We have to respect them but also take them on and play the way we play.
"When I watch Barcelona I expect them to win but you have to believe in yourselves. We have given them tough games in the past and we are ready to try to do that again."
Nevertheless Lampard is under no illusions about the scale of the task in front of Chelsea, who come into the game with useful momentum following the 5-1 FA Cup semi-final thrashing of Tottenham at Wembley.
Lampard believes Messi has already surpassed Diego Maradona in the pantheon of all-time greats.
"He has improved since we played them in 2009 and he was a fantastic player then. The levels he has taken his game to is something I have never seen before," Lampard said.
"I grew up on Maradona. He was my idol and I think Messi has taken it to higher levels than him. To get close to 70 goals is crazy. He deserves it. He is the best player in the world."
Chelsea's last meeting with Barcelona came in the semi-finals three years ago, when Andres Iniesta's injury-time equaliser and a string of dubious refereeing decisions denied the English side a place in the final.
Lampard said Chelsea would not be entering the match motivated by a sense of revenge.
"That's not really in our thoughts," Lampard said. "They have moved on from three years ago and we have changed as well."
Chelsea's interim manager Roberto Di Matteo is likely to target Barcelona's back four as he attempts to mastermind what would be the greatest win since he took over from the sacked Andre Villas-Boas in March.
Di Matteo is adamant that there are weak links in Barcelona's armour. "We just need to exploit them," Di Matteo said.
-AAP