Frank Lampard has warned Manchester City need to be flawless when they face Barcelona in the Champions League, saying that one mistake could see them knocked out of the competition.
Lampard, 36, captained Chelsea as they saw off Bayern Munich to win the trophy in 2012, while he also scored in the Blues' 2008 final defeat to Manchester United.
The former England international helped the West London side knock Barcelona out in the semifinals in 2012 and has lost only two of 10 Champions League matches against the Catalan club.
However, he and Chelsea were eliminated in controversial circumstances by Barca in the last four in 2009 and in the last 16 in 2006, while City went out 4-1 on aggregate to the Spanish side last season.
City welcome Barca to the Etihad Stadium for the first leg of their last-16 tie on Feb. 24, and Lampard says he and his teammates must be on top of their game if they want to progress in the Champions League.
"It is difficult to win against these teams -- but to go on and win it you have to win matches like this," Lampard told City's official website. "We have to be on the ball for both games against Barcelona because you're playing against such high quality that one lapse of concentration will cost you the game."
City have never reached the last eight of the Champions League before, but Lampard was part of the first Chelsea side to reach the semifinals and then the first to win the whole competition.
And the midfielder believes City can emulate his former club, adding: "I've had lots of good and bad experiences in the Champions League in that I've been knocked out in big games and had big decisions go the wrong way.
"There were many years when I was at Chelsea when success was very close -- I think I've played in four or five semifinals and also lost a final against Manchester United, so to actually win it in 2012 was extra sweet and undoubtedly the best night of my career to date.
"I'd love to see City do the same and I think it's the club's next step. There will be disappointments along the way and I know that there have been some hard times in this competition in recent years and Chelsea had many hard times as well, but that's what happens when you are up against the best."
While City have struggled to replicate their success in the Premier League on the European stage, Lampard is convinced they will win the Champions League one day.
"For me the Champions League is the best club competition in world football," he said. "Playing against a team like Barcelona and the greatest club teams in Europe when all the eyes of the world are on you is hard to beat.
"This is a trophy every big club needs in their collection, and the way City are heading it is one that will happen at some point. These sorts of games are the ones you have to win if you are going to go on and win the competition."