Barcelona, 4-1 aggregate victors when the teams met at this stage last year, had found scintillating form since a l-0 loss to David Moyes's Real Sociedad on January 4, winning their next 11 games in all competitions.
But that run came to a juddering and unexpected halt on Saturday when they lost 1-0 at home to Malaga in La Liga after a lacklustre performance completely out of keeping with recent displays.
Roughly 40 minutes after the final whistle sounded at Camp Nou, City set about constructing a 5-0 victory at home to Newcastle United that allowed them to cut Chelsea's lead in the Premier League to five points.
Following on from a 4-1 win at Stoke City, which had seen the English champions end a four-game winless run, the stylish victory, inspired by David Silva, provided further proof that their mid-winter slump has ended.
For City manager Manuel Pellegrini, it was a sign that his side are once again a "scoring team", but for all the optimism the performance engendered, it will not erase memories of what happened the last time Barcelona crossed his path.
Both games last season followed similar patterns, with Lionel Messi twice opening the scoring, Dani Alves twice adding a late goal, and City twice having a defender sent off -- Martin Demichelis in the first leg and Pablo Zabaleta in the second.
Demichelis's dismissal at the Etihad, for a last-man foul on Messi that yielded a penalty from which the Argentine put Barcelona ahead, left Pellegrini apoplectic and he was given a two-game touchline ban by UEFA for accusing Swedish referee Jonas Eriksson of impartiality.
But while Vincent Kompany's late goal in the return leg meant that City belatedly landed a blow on their opponents, there were few complaints about the aggregate scoreline.
- Toure suspended -
"It is important not to make the mistakes that we made last year," said Pellegrini, whose club have never reached the quarter-finals.
"In both those games we played with one player less
In the knockout stage you have to not concede goals, and with a player sent off it is very difficult
You have to think of the match as being 180 minutes, not 90."
Now under the tutelage of Luis Enrique, Barcelona are much-changed, with the team configured to move the ball as quickly as possible to a devastating front three of Neymar, Luis Suarez and Messi, who has already scored 14 goals in 2015.
When Barcelona have come unstuck this season, as against Malaga and Real Sociedad, it has tended to have been when teams have scored early against them and then defended en masse, but defender Gerard Pique believes City will not approach the tie so cautiously.
"It is one of the games of the year, the most important until now," said the former Manchester United centre-back.
"They will try to attack us and that suits us
It has been proven over the past few months that we are better against teams that attack us because we can counter-attack."
The hosts will be without Yaya Toure as he completes a three-game ban, but City's group-stage great escape -- a stirring 3-2 win against Bayern Munich, in which Sergio Aguero scored a hat-trick, and a 2-0 victory at Roma -- was orchestrated without the giant Ivorian in their ranks.
With James Milner expected to return from a knee injury and January signing Wilfried Bony in line for his Champions League debut, City are otherwise at full strength, but Aguero, Zabaleta, Gael Clichy and Edin Dzeko are all one booking away from suspension.
Barcelona's group-phase progress was rather more serene, despite a 3-2 loss at Paris Saint-Germain, and their only absentees are long-term injury victims Thomas Vermaelen and Douglas.
Source : AFP
Source: AFP