Lionel Messi Barcelona Manchester City Joe Hart
Barcelona forward Lionel Messi celebrates after scoring past Manchester City goalkeeper Joe Hart from the penalty spot in their Champions League last 16 first leg game, 18 February. Reuters

FC Barcelona manager Gerardo Martino believes that consistency, on Barca's part, will define the outcome in the second leg of their Champions League round-of-sixteen tie against Manchester City.

The Catalan giants have the advantage coming into the match on Wednesday, winning 2-0 at the Etihad in February, but have since lost two of their three La Liga outings to Real Sociedad and, recently, Valladolid last Saturday.

"After the match in Valladolid I said we made mistakes but under different circumstances - because all our defeats this season have been different. There's not a specific reason for us being inconsistent," Martino told uefa.com.

"We need to be more consistent at this stage of the season to maintain our chances of winning all three competitions [Liga, Copa del Rey and UEFA Champions League]."

"We have talked a lot individually and as a group, but this is a different competition, we have a positive result behind us and we played well in Manchester."

Meanwhile, City assistant manager, Rubén Cousillas, will oversee the proceedings in lieu of Manuel Pellegrini, who will be serving a suspension.

The second-in-command hopes that his squad will be able to forget the pain of elimination from the FA Cup in the hands of Wigan on Monday, and focus on their upcoming clash, hoping to overturn the tide away from home.

"All clubs go through tough times at some point in the season, but I don't think that will be a determining factor tomorrow," said Cousillas.

"We had a big sense of frustration because we wanted to be back at Wembley and win another cup, but Wigan surprised us. We have turned the page and we have experienced and quality players, which means we are more united than ever and we have forgotten everything in preparation for tomorrow."

"The decisions are taken by [Manuel] Pellegrini. I have worked with him for 13 years and I know what he wants. Tomorrow he can't be on the bench [because of suspension] so it's up to me to make substitutions, etc."

Probable Starters:

Barcelona (4-3-3) - Valdes; Alba, Alves, Pique, Puyol; Fabregas, Xavi, Busquets; Pedro, Sanchez, Messi

City (4-4-2) - Hart; Kolarov, Zabaleta, Lescott, Kompany; Silva, Nasri, Fernandinho, Toure; Dzeko, Aguero

Schedule and Live Streaming Information (Click on "click here" for online links):

March 13, 2014, 5:45 am (Australian EST)

Australia [click here]

U.S. [click here]

UK [click here]

Canada [click here]

Latin America [click here]

South Africa [click here]

Middle East [click here]

India [click here]