Pique, the former Manchester United defender, accepts that Barca may have lost some of the aura of greatness that surrounded their European triumphs of 2009 and 2011.
Yet as leaders of the Primera Division heading into the first leg against City at the Etihad Stadium - albeit only on goal difference - Gerardo Martino's side are hardly a spent force.
Pique said: "I think that maybe they (opponents) don't fear us as before because in the last two years we did not win the Champions League, but I think they still respect us.
"We are a team with a lot of players who have won the World Cup, Champions Leagues and leagues.
"I think we can still be the best but we have to show to the world that we can do it.
"This is a great opportunity to show we are top players and can win here."
Chelsea manager Jose Mourinho, who worked at the Nou Camp under Sir Bobby Robson earlier in his career but has since had a fractious relationship with the Catalan giants, claimed City would be facing "the worst Barcelona of many many years".
The former Real Madrid coach was quoted as telling ITV late on Monday evening: "Of course by history Barcelona is the favourite, but this Barcelona, this season, is showing that it is not the same in previous years.
"Of course, they have (Lionel) Messi - he is special - and they have more than him. But I think this is the worst Barcelona of many many years, so City have a chance."
Pique, 27, was speaking to media as Barca arrived at City's Eastlands venue to train ahead of the match.
The trip has brought back happy memories of his early career, having joined United - from the Barca youth set-up - at the age of 17.
He was lured back to Barcelona in 2008 and has since become an integral member of their star-studded side.
Pique said: "It is very special (to be in Manchester).
"I was 17 when I came here, a child. Obviously I would have liked to have played more but it was a very special three years, I learned a lot.
"I always say Manchester United is my second team after Barca and Sir Alex Ferguson is the best."
United have endured a difficult campaign this season while City have been highly impressive in maintaining a challenge in four competitions.
City have bold ambitions to become a European force and manager Manuel Pellegrini believes they have overtaken United as Manchester's dominant force.
Yet if Pique was to leave Barca, there is still only one other club he would like to play for.
He said: "What do you think? If I had to choose one it would be United.
"But I am very happy in Barcelona - it is the club of my life and I am not thinking of leaving."