Andres Iniesta and Barcelona are refusing to underestimate Celtic ahead of Tuesday night's UEFA Champions League showdown.
The two sides are preparing to meet in Group G at Camp Nou and sit first and second, respectively, in the standings after two matches.
Barcelona have a 100 per cent record in Europe this season and back-to-back wins over Celtic would book Tito Vilanova's team a place in the knockout stages.
But Iniesta has been impressed by Neil Lennon's side in their draw with Benfica and win over Spartak Moscow in Russia and he knows Barcelona cannot be complacent.
Iniesta, who faced Celtic in the Champions League in 2008, told Sky Sports: "Barcelona are superior to Celtic but we have seen the experience of Spartak Moscow.
"At home, an error could change the match and we need to work to 100 per cent from the first moment. These matches against Celtic are decisive for us."
Iniesta, meanwhile, is in no doubt about Barcelona, who won a 5-4 thriller at Deportivo La Coruna at the weekend, deserving the widespread praise they receive for their style of play.
"This Barcelona is incredible," he said. "I insist we now play the best football in the world.
"I, as a spectator, would always pay for a ticket to watch Barcelona because the spectacle is guaranteed."