Manchester City's Samir Nasri, Wilfried Bony and Stevan Jovetic during trainingCarl Recine/Reuters
Barcelona's passage to an eighth straight Champions League quarterfinal could be blocked by a Manchester City team desperate to end three years of underachievement in the competition.
For the English champions, there's also the matter of avenging an exit at the hands of Barcelona at the same stage last season, when losses in both legs of the last 16 – for a 4-1 aggregate defeat – demonstrated the gulf between the clubs.
So what has changed in the last 12 months? Barcelona has a different coach in Luis Enrique, an improved strikeforce after Luis Suarez joined Lionel Messi and Neymar, but perhaps a less dominant midfield as the impact of Xavi Hernandez starts to wane.
Before Saturday's 1-0 loss to Malaga, Barcelona had won 11 consecutive games in all competitions to bring an end to a worrying period that featured below-par performances and speculation about a falling-out between Messi and Enrique.
While the Spanish team breezed into the knockout stage with a match to spare, City squeezed through thanks to an astonishing late turnaround against Bayern Munich in its next-to-last group game and then a 2-0 victory in a win-or-bust match at Roma.
City failed to advance from its Champions League group in back-to-back seasons, but has progressed for two seasons in a row to finally make an impact in Europe and reward the heavy spending of its owner from Abu Dhabi, Sheikh Mansour bin Zayed bin Al Nahyan, since 2008.
City also appears to have gotten over a slump in results over January, with big wins over Stoke and Newcastle in its last two Premier League games reviving its title defence and rediscovering the attacking swagger that characterized the team's last few seasons.
City manager Manuel Pellegrini believes it could be different this time against Barcelona: his team is fresher – owing to early exits in both domestic cup competitions this season – and has gained more experience in Europe.
Barcelona, spurred on by the sparkling Messi, starts as favourite but expect a more streetwise City over the two legs compared to last year's meetings.
Here are some things to know about the first leg:
MAD MESSI
One image summed up Barcelona's loss to Malaga: Messi slamming his fist into the turf in frustration after he had again surrendered possession in a failed dribble.
Nothing worked for Messi on Saturday. His incursions into the thick of the defence ended up with him being dispossessed, while his crosses rarely hit their mark. He barely had a shot on goal.
The positive for Barcelona is that it's difficult to imagine Messi – and Neymar and the rest of the team – playing as poorly in attack for two consecutive games.
Before Malaga, Messi had scored 14 goals in an 11-game winning streak, only failing to find the net once, as he increased his season total to 37 goals.
FULLY STOCKED
Enrique will have the entire squad at his disposal, with no major injuries reducing his stock of first– or second-choice players. Xavi could get a start after missing the loss to Malaga but his spot in midfield may again go to Ivan Rakitic, who went on as a second-half substitute on Saturday.
Javier Mascherano also started on the bench over the weekend and will likely return to anchor Barcelona's defence alongside Gerard Pique.
Suarez will make his first appearance in England since his move from Liverpool. He is the reigning player of the year in English football but hasn't been as prolific in Spain.
NO TOURE
City will be without Yaya Toure – a former Barcelona player – as the midfielder is serving the third and last match of a suspension from midway through the group stage.
Versatile midfielder James Milner is the only injury doubt after missing Saturday's 5-0 win over Newcastle with a knee problem, although he trained on Monday.
ON THE ATTACK
Pellegrini has been accused of being too bold and inflexible with his lineups against the top teams in Europe over the past two seasons by playing two strikers and an attacking midfield. The two games against Barcelona will determine if he has learned his lesson.
Malaga may have given City the blueprint for beating Barcelona – pack as many men inside the area as possible, cede the flanks and send three defenders at Messi every time he touches the ball. Don't expect Pellegrini to follow that guide to the letter.
"We are going to try from the beginning ... to be an aggressive team and to try and score goals," Pellegrini said.
With Toure out, Pellegrini has to decide whether to play a 4-5-1 formation, with Sergio Aguero as the lone striker and with Fernandinho and Fernando as his holding midfielders as they were in the win in Roma.
Alternatively, Pellegrini must choose between Edin Dzeko and new signing Wilfried Bony as Aguero's partner in a 4-4-2.