Messi has occasionally worn the armband before when Andres Iniesta, who replaced Xavi as skipper in 2015, missed a game.
The Argentine has also led his country, with only mixed results.
With Iniesta moving to Japan, Messi takes the job full time starting in Tangiers after Sergi Roberto captained an inexperienced Barca squad during the club’s recent tour of the United States.
Messi can eclipse Iniesta in another way in the Supercup, as both have won a club-record 32 trophies with Barca and victory on Sunday would break the tie.
“We’re excited about playing for our first trophy of the season,” said Barcelona coach Ernesto Valverde.
The match marks a break with tradition. Since its return in 1982, the competition has been played over two legs with each team hosting one game.
This season, with Sevilla in the Europa League and Barcelona keen to play in the lucrative International Champions Cup exhibition tournament in the United States, the Spanish football authorities switched to a single-game format.
They also moved the match across this Straits of Gibraltar to Morocco, where Spanish football is keenly followed.
Sevilla, who therefore lost an attractive home game against one of Europe’s most glamorous teams, protested to no avail.
On the even of the game, the Spanish football authorities made another ruling that helped Barcelona, announcing that the normal restrictions on non-EU players in Spanish games would not apply.
“That this comes out one day before the match is, at the very least, curious,” Pablo Machin, the new Sevilla coach, told a pre-match press conference on Saturday.
One of Barca’s South Americans, Brazilian Philippe Coutinho, obtained his Portuguese passport on Friday, but the decision means that Valverde can play three recent major signings Chilean Arturo Vidal and Brazilians Malcolm and Arthur together.
Vidal “is a footballer used to playing in important games,” Valverde said on Saturday.
Barcelona could also give a debut to Clement Lenglet, a French defender they bought from Sunday’s opponents.
Barcelona can still add more players because the Spanish transfer window does not close until the end of August.
“In training the players who have arrived have shown a very high level,” Gerard Pique was quoted as saying on the Barcelona web site on Saturday.
“We’ve bought very well and will have a very competitive team regardless of whether other players come in.”
The game pits Barca, who won the Spanish double, against the club they thrashed 5-0 in the final of the Copa del Rey and who finished a distant seventh in La Liga.
“Sevilla is a very competitive team and they are doing things very well and tomorrow will be a difficult game,” said Pique.
Barcelona follow Sunday’s game with a home friendly against Boca Juniors on Wednesday before kicking off the defence of their Spanish league title at home to Alaves next Saturday evening.
“They are a super team and specialise in winning finals,” Machin said. “But soccer is one of the few sports where an underdog can beat the favorite.”
“Competing is the key word.”
Sevilla played on Thursday, beating Zalgiris Vilnius 1-0 at home in a Europa League third qualifying round first-leg game.
After Sunday’s match, they must cross Europe to defend that slender lead in Lithuania next Thursday before kicking off their domestic league campaign at home to Villarreal on Sunday.
“It is more important to progress in the Europa League than win the Spanish Super Cup”, Joaquin Caparros, Sevilla’s director of football told the Cope radio station.
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