Former midfielder Xavi was this month appointed as Barca's head coach following the dismissal of Ronald Koeman.
A penalty from Memphis Depay gave the Catalan giants a 1-0 victory over Espanyol in his first game at the helm last weekend.
The Blaugrana had 11 shots in the first half at Camp Nou – the most they have had in the opening 45 minutes of any game this season – but had also faced 12 by the final whistle, the most in a Barca boss' opening LaLiga game in charge since Frank Rijkaard (17) in August 2002.
A potentially pivotal Champions League clash with Benfica is next up on Wednesday (AEDT), and Messi believes his former team-mate Xavi has what it takes to get the Catalan giants back on track.
"Barcelona will grow with Xavi. He is a coach who knows a lot and knows the club perfectly," Messi said.
Messi will be hoping to get his hands on the Champions League trophy this season, having linked up with Neymar and Kylian Mbappe at Paris Saint-Germain.
While the Argentina captain acknowledged they are among the favourites for European success, he feels Mauricio Pochettino's team have plenty of work to do to reach the required level.
"Everyone says that we are the favourites and I will not deny that we are one of the candidates because of our name, but we still need things to be a really strong team," he said.
PSG will book its place in the Champions League round of 16 if it beats Manchester City at the Etihad Stadium on Thursday (AEDT).
Messi has scored seven goals in as many Champions League appearances against City, who lost the reverse fixture 2-0 back in September.