City and Barca may be hitting form but, with Xavi feeling his age and Dzeko not quite top drawer, every team has its weaknesses...

By Rik Sharma

Published: 05:42 EST, 16 February 2014 | Updated: 13:45 EST, 16 February 2014

On Saturday Manchester City sent a statement of intent to Barcelona with their FA Cup win over league leaders Chelsea.

And two hours later, Barcelona fired right back with a thumping win over Rayo Vallecano.

On Tuesday the sides clash in the Champions League last-16 and before then will be scouring videos of each other, searching for weaknesses.

Here, Sportsmail exposes the chinks in each side’s armour.

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BARCELONA

Flank trouble

One of Barcelona’s biggest offensive strengths can be their greatest defensive weakness.

Jordi Alba and Dani Alves offer a lot going forward. Sometimes when you watch them play, they’re almost auxiliary wingers. However, both of them are susceptible to defensive mistakes, particularly positional errors.

In the recent 3-2 defeat by Valencia at the Nou Camp, Sofiane Feghouli tormented the Spanish left-back, creating two goals and eventually getting the frustrated Alba sent off.

Alves meanwhile, has been going through a rocky patch and it led to him being dropped for the clash against Sevilla on February 9 - a game he would have enjoyed playing in, given that they were his former side.

In the two matches since then he has impressed, although Real Sociedad and Rayo Vallecano don’t have players nearly as dangerous as David Silva.

City could get great joy down the flanks, with Jesus Navas’s pace a real weapon on the counter-attack.

Silva, meanwhile, had too much for Branislav Ivanovic who is a stouter defender than Alves.

Sagging in the middle

During their recent period of dominance in Europe, Barcelona’s central midfield was one of their key tools in controlling matches.

And individually, it’s still packed with talented players - but something’s not quite adding up.

After their humiliation by Bayern Munich last season, it’s clear that a little more speed and power would be useful.

In January, Xavi made his 700th appearance for Barcelona. It was a day celebrated by Blaugrana fans and he deserved the accolades thrust upon him.

At 34 years old, he is, along with Andrea Pirlo, one of the wisest heads in the game and his technical abilities are still superb.

Tata Martino rested him on Saturday night, which means he’s likely to start against Manchester City. In turn, that means Cesc Fabregas is likely to step out of the centre and become part of the forward line, as he fulfils similar functions to Xavi in the middle.

Andres Iniesta, who was back to his best against Rayo after a dip in form, is likely to join him, along with Sergio Busquets.

The problem is that only Busquets has the physicality to deal with the rampaging Yaya Toure. And if City play their cards right, he will have his hands full with Silva - and/or Samir Nasri - drifting into his zone.

Toure, with Javi Garcia alongside him, can help overpower Barcelona’s core.

If Fernandinho was fit to start then City would have a good chance of severely breaking up Barcelona’s play, but Garcia impressed against Chelsea and will need to do the same again to match the absent Brazilian.

A lack of defensive diligence

There was an instance on Saturday against Rayo Vallecano when Lionel Messi had the ball on the edge of the penalty area, with Barcelona players flooding forward, but was dispossessed.

Rayo broke quickly and Messi, having lost it, followed the play backwards.

He ran deep in to his own half, but despite having three different opportunities to take re-gain possession refused to commit and waited for a team-mate to step in.

It didn’t cost Barcelona - they were already winning and Victor Valdes pulled off a fine stop from the resultant Rayo shot.

But in the modern game there is little scope for players not pulling their weight in a defensive sense - even attackers.

Of course, if you are going to make an exception, the man crowned the best player in the world four times, who broke a record and pulled level with the legendary Raul on La Liga goals, is a good candidate.

But against Manchester City, every margin, every edge will be important.

Centre-backs Gerard Pique and Javier Mascherano have been suspect in recent weeks and, were Sergio Aguero fit to start, you’d bet on him to score.

Veteran defender Carles Puyol impressed on Saturday and was hooked with twenty minutes to go. He was spotted icing his knee on the sidelines, presumably as a precaution - although City will hope he is absent.

MANCHESTER CITY

Goal threat

It would have seemed insane a few weeks ago to call City out for a lack of attacking threat.

They were the Premier League’s danger side, the one team you could rely on to put a hatful past terrified opponents.

But they drew two blanks before their 2-0 win over Chelsea on Saturday, and without Aguero simply don’t have the same menace.

Alvaro Negredo has been suffering from an arm injury and was left on the bench against Chelsea, but should lead the line on Tuesday night.

Edin Dzeko is a decent forward but not a great deal more.

Stevan Jovetic, meanwhile, offers some guile and was the man who opened the scoring against Chelsea.

However, at the moment he simply isn’t in the world’s top bracket.

Barcelona, however, have a lot of options. Messi scored and assisted more goals against Rayo than City have netted in Feburary.

Neymar has just returned to action, coming on as a substitute and scoring a brilliant goal.
Both Pedro and Alexis Sanchez have been in the goals this season and are distinct threats.

Fabregas, who is likely to join Messi and one of those two in the attacking trio, also has a good scoring record this season.

Manuel Pellegrini will be looking to secure a good advantage in the home leg, but may be frustrated by his strikers.

A lack of experience

This Barcelona team are Champions League veterans. Most of them have lifted the trophy before. Some several times.

Xavi and Puyol have made the most league appearances for their team in the Catalonian club’s history.

A quick run-down of the likely Manchester City starting line-up (Hart, Zabaleta, Lescott, Kompany, Kolarov, Toure, Garcia, Navas, Silva, Jovetic, Negredo) reveals that only Toure has won the Champions League - with Barcelona.

With the exception of Joe Hart, only Pablo Zabaleta in that eleven has been at the club for more than five years.

City are only accustomed to failure in the Champions League and although that will change at some point, it’s a disadvantage.

Pellegrini’s bad maths could have cost them at an earlier stage in the group.

It’s difficult to imagine Barcelona making a mistake like that.

The Catalan side have men who know just what it takes to beat some of the best sides in Europe, even if physically they are out-matched.

Barcelona’s star power is not to be doubted either. In Messi, City will be facing an adversary with a lure and a danger they have not encountered before. Neymar too, although he is likely to start on the bench at the Etihad.

Messi’s only rival, Cristiano Ronaldo got the better of them last season, scoring a last minute winner at the Bernabeu.

Roberto Mancini’s team fared better at home, but it was Sergio Aguero who earned them a draw.

Focus too much on trying to stop Messi and the other Barcelona forwards will relish the space. Don’t pay him enough attention and suffer the consequences.

Can’t keep it tight

Manchester City have conceded more goals than the two sides ahead of them in the table - Arsenal and Chelsea.

They suffered goalkeeping calamity after calamity earlier in the season, which led to Joe Hart being replaced by Costel Pantilimon.

The Englishman has regained his place between the sticks, but you still can’t shake the feeling that there’s a mistake in him.

City have shipped some foolish goals in 2014, conceding twice against each of Swansea, Cardiff and Championship Watford.

They can’t settle on a defensive partnership, partly because of injury - Matija Nastisic the latest casualty.

Joleon Lescott filled in for him against Chelsea and did an excellent job, but he was only faced by Samuel Eto’o, with Chelsea’s midfield too deep to pose many problems for City’s centre-backs.

At times Eden Hazard attacked down the left and Pablo Zabaleta found him tough to control, even with support from the midfield.

If Barcelona stick to their guns and come out with the attitude we’ve come to expect from them, they could overload City from the start.

Vincent Kompany and Lescott will need to play the game of their lives to keep Messi quiet.