Neymar Barcelona
Neymar will be a key figure for Barcelona in their Champions League first leg tie against Manchester City. Reuters

Two of the most exciting attacking teams in Europe take centre-stage on Tuesday night with Barcelona paying a visit to the fortress Etihad for their Champions League first leg last 16 encounter against Manchester City.

As is always the case, certain battles will decide the state of the match at the end of the 90 minutes, and below is a look at six key battles.

Lionel Messi vs pretty much every Manchester City defensive body: Messi is Messi, and even at 50 percent he is near unstoppable, even for a team of the calibre of Manchester City.

If Messi decides to have one of those how-on-earth-did-he-run-past-five-defenders-to-score-that-goal days, then City will be lucky to still be alive in the tie going into the second leg.

The best chance for City to nullify Messi's threat is to starve the Argentine off the ball as much as possible, and the midfielders Yaya Toure and Ferandinho, is passed fit, will come into play there.

Yaya Toure vs Sergio Busquets: City do not have a conventional No. 10, with Pellegrini playing with two strikers and wingers in David Silva and Samir Nasri, if selected, that like to drift inside, and Jesus Navas who likes to hug the touchline.

So, that leaves Busquets with the job of tracking those bursting runs from Toure, a former teammate.

Alvaro Negredo vs Gerard Pique/Javier Mascherano: With Sergio Aguero out injured, the onus will be on Negredo to get the goals, and the Spanish striker might just fancy himself against the Barcelona central defenders.

Pique will be keen to keep his international teammate quiet, but with the pace and verve that City attack with, it will definitely be far from easy.

David Silva/Samir Nasri vs Xavi/Iniesta: Xavi and Andres Iniesta, assuming they will be the other two of the three central midfielders, are the awesome twosome that make Barcelona talk, that keep that ball pinging from one place to the other, and orchestrate most of the Spanish side's attacks.

At the other end, there is Silva and Nasri, who has come into his own in a Blue shirt this season. Nasri made a scoring comeback from injury at the weekend, and the French playmaker will be keen to outshine his more illustrious opponents.

Silva very rarely has a bad game, and the former Valencia man will also want to show his prowess against the Spanish giants.

Neymar vs Pablo Zabaleta: Neymar likes to drift in from the left and cause havoc inside the penalty area, and Zabaleta, one of the English Premier League's best right-backs, will have to play out of his skin to keep the Brazilian, who scored a brilliant goal against Rayo Vallecano at the weekend, quiet.

Also, Zabaleta will look to bomb forward as often as possible down the City right, and Neymar's defensive discipline will be put to the test.

Joe Hart vs Victor Valdes: With the two teams having a penchant for scoring goals, plenty of efforts on target can be expected. The goalkeeper that plays better might just decide the outcome of the fixture.

Both Valdes and Hart are prone to howlers and have the capabilities of pulling off blinding saves - on such a big occasion, however, neither will want to make the mistake that costs their team a loss.