"Many players came into this game after time off, having only just returned this week, and this was obvious".
Sevilla have threatened to withdraw from the Spanish Super Cup scheduled to be played on Sunday night after the Spanish football federation (RFEF) said that there would be no restrictions on players from outside the European Union for the tournament.
But it was Dembele who sealed the game when he lashed a shot home from 20 yards via the underside of the crossbar in the 79th minute.
Barcelona and Sevilla have both been busy throughout the summer transfer window, despite the latter spending less than half of the former on new signings.More news: Harry Kane's Premier League Record In The Month Of August Is Shocking
Africa may be unfamiliar surroundings for Barcelona - but they will glimpse the familiar sight of silverware should everything go according to plan against Sevilla.
Gerard Pique equalized three minutes before halftime when he finished off a free kick by Messi that hit the post and ricocheted off the back of goalkeeper Tomas Vaclik - and again off the upright - before falling to the Barcelona defender.
Sevilla almost restored their lead just after the hour mark but Franco Vazquez's glancing header shaved the top of the crossbar. But his first season at Camp Nou was limited by injuries as Dembele struggled to replace the hole left by Neymar after he went to Paris Saint-Germain.
It was Barcelona's 13th Supercup and sixth in the last nine seasons. He was able to create space where there wasn't much against a team that sat back more than we expected.More news: Erdogan says US set deadline for pastor's release
"We are happy because we were competing for a title against a great opponent", he said.
Sevilla qualified for Sunday's match as last season's Copa del Rey runners-up after Barcelona won the league and cup double.
The match takes place tonight at 9pm in Tangier, Morocco, with this year's competition the first time the cup will be decided by a one-off tie as opposed to a two-legged affair.
Sevilla faces Zalgiris on Thursday after winning their first match 1-0.More news: Everton set to land Chelsea defender Kurt Zouma before transfer deadline window
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