"I think we have become more macho and we have all stepped up from last year," he told a media briefing at the launch of the official match ball for the May 28 final at Wembley.
The France forward said he was convinced Arsenal would make up for last season's 6-3 quarter-final defeat by "the best team in the world" and reach the last eight again.
They have given themselves a chance of making progress after coming from behind to beat the Spanish champions 2-1 in the first leg of their last-16 tie at the Emirates Stadium on February 16.
Although the 23-year-old forward conceded Barcelona start as favourites to advance, he said Arsenal's players were no longer intimidated by the likes of Lionel Messi, Xavi and Andres Iniesta, the creative forces in Pep Guardiola's glittering team.
"We approached the game differently this year. Last year we were a little scared of Barcelona because they are fantastic and play amazing football and we were surprised how good they were.
"This year we said, 'Look, they are fantastic and if we lose to them it will be normal because they are the best team in the world.' So there was no pressure on us and we played our normal game and showed everyone we can beat them and be at their level.
"We are more macho, physically and psychologically, Some of us, like Theo Walcott, Jack Wilshere, even myself, we have all stepped up. "We are stronger. All of our players can compete with all of theirs."
SHOCK DEFEAT
Nasri was sitting in the dressing room at Wembley Stadium where the disconsolate Arsenal team returned after their shock 2-1 defeat by Birmingham City in Sunday's League Cup Final.
He said that setback had not dented their self-belief as they, along with Chelsea and Tottenham Hotspur, attempt to become the first London side to lift the European Cup.
Chelsea host FC Copenhagen in their last-16 tie after a 2-0 win in the first leg in Denmark while Spurs are 1-0 up against AC Milan after winning their opener in Italy.
Nasri knows the path he would like Arsenal to take to surpass both of their London rivals.
"If we beat Barcelona, I would love to play one of the other London clubs in the final and I want Arsenal to be the first club from London to win the Champions League.
"But my dream would be to play against Marseille in the quarter-finals, then Tottenham in the semi-finals, then Chelsea in the final," he added.
Olympique Marseille were held to a 0-0 draw by Manchester United in their first leg in France.
"I want Marseille to beat Manchester United. It would be special for me to play against Marseille. I was born there, I grew up there, I played for Marseille for 10 years and it's something I would love to do."
Before that though, Arsenal need to get past Barcelona and Nasri is under no illusion just how hard that task will be, even though he is very optimistic it will happen.
"More important than stopping Xavi or Iniesta is sto
