After transfer requests, contract leaks and continuous questions over his future, the Argentine has been the focus of many a headline this season.
"I think that Messi, even though he can have off-the-pitch things or difficult moments or decisions regarding his future, shows in each game that he's still the Messi of all the games he's played since he started out at Barcelona," Pellegrini said in his pre-match press conference.
"He's a unique and different player, one who has carried Barcelona to glory for many years.
"I don't think there's anything in particular that we can take advantage of [with him].
"The decisive factor is that we have to have a good game, with personality, knowing that we're up against good players.
"Don't make mistakes, have high individual performances and keep that spirit the team has shown in the last two and a half months."