Andres Iniesta says Barcelona will have to beat "one of the best teams in the world" if they are to pip Arsenal to a place in the Champions League quarter-finals.
Barcelona are regularly described as the greatest club side on the planet, not least by Gunners boss Arsene Wenger at the weekend, but Iniesta says their last-16 clash at the Emirates tonight is a match against equals.
Injury meant Iniesta was not able to play when the sides met in the quarter-finals of last season's competition, where a 2-2 draw followed by a 4-1 thrashing at the Nou Camp sealed Barca's passage, and is looking forward to featuring this time.
"I couldn't play last year but it was an excellent match here, very interest and a lot of goals," said the World Cup winner.
"There were some good moments for us but they put us under a lot of pressure. They are going to try and play a good game again and we need to play really well because this is one of the best teams in the world.
"This tie will be decided in the next match when we return to Barcelona. It is the Champions League, we find ourselves against the best in the world so I don't think anyone will think the tie can be won today."
Guardiola has promised to remain true to the Barcelona way tonight, with possession and attack the order of the day, though he admits Wenger's style of play could leave his side on the back foot if they are not on top form.
"With Arsenal if you are not well prepared you will be chasing shadows," said Guardiola.
"I like to watch Arsenal play football but I don't like to play against them. Of course I have worries about the game that Arsene Wenger plays. Theo Walcott has some good moments, Wenger is an incredible coach and Robin van Persie is a very mobile player who has a lot of influence.
"When you play Arsenal you know what is required of you. The players of Barcelona know what we have to do.
"We will try to play attractive football, we have for the last 20-25 years. We might lose, we might win but we will always play attractive football for our fans.
Arsenal playmaker Samir Nasri, the Gunners' 14-goal top scorer, could feature as Wenger ponders whether to rush him back after a fortnight out with a hamstring injury.
Despite his threat, Guardiola admires the Frenchman and wants him play.
"If Nasri doesn't play they still have (Tomas) Rosicky or (Andrey) Arshavin but Nasri is an incredible player.
"I hope Nasri can play. I always prefer to play the teams who have the best players."