Pique, part of the Barca team that lost 1-0 at home to Malaga in La Liga on Saturday, also believes the first-leg game at the Etihad is an opportunity to put things right after the defeat at Camp Nou.
"Having a game every three days is great because it's a chance to prove ourselves again," the Spain international told reporters at the official press conference in Manchester. "We get to play again and forget about Saturday a little bit.
"You never forget about a defeat at Camp Nou, but it's the chance to come here and get a good result to take back to the second leg."
And he added: "City are one of the five best teams in the world and the Champions League is the most important competition, the most prestigious one. Now the most important thing is to advance to the quarter-finals."
The two teams also met in the Champions League last season, when Barca won 2-0 away from home to set up a 4-1 aggregate win, but Pique believes this tie will be much more difficult.
"It will be a similar game to last year, with two teams who want the ball," the centre-half said. "In the first game last year, [Martin] Demichelis' red card played a big part. Without that it would have been much harder.
"We will be serious, try to defend well and take advantage of our fantastic forward line."
After Saturday's loss, more speculation emerged that the players are unhappy with Luis Enrique, but Pique dismissed those reports and claimed the squad are fully behind their coach.
"There is no unsettled atmosphere surrounding Luis Enrique," he said. "The team are behind the coach. While we were winning, nobody talked about any of that."
The defender was also asked about the absence of former team-mate Yaya Toure and says the midfielder's suspension could help Barcelona.
"Yaya is such an important player," he said. "He has so much quality. I was looking at some statistics on television and when he is out, you definitely notice the difference."