Neymar and Liones Messi are the players who can cause the most damage to Manchester City. [Reuters]

Manchester City's last 16 opponent Barcelona have started the season with some doubts under new manager Gerardo Martino, even though they are top of the La Liga table and won their Champions League group. The Catalans still miss Pep Guardiola and some pundits suggest that Barcelona's golden era is now a thing of the past.

How They Got To The Last 16: They secured top spot in Group H in the last game, beating Celtic 6-1 in their best performance of the season. The Catalans won their three games at home but they lost away against Ajax and managed only a draw in their trip to Milan. They scored 16 goals and conceded five in the six games of the group stage.

Who Can Cause the Most Damage: Argentine star Lionel Messi, goalkeeper Victor Valdes and summer signing Neymar are currently the key players at Barcelona, with Xavi Hernandez and Andres Iniesta far from their peak form so far this season.

Messi and Valdes are currently injured but both players are expected to return into action at the beginning of 2014 so they will be fully fit to face Manchester City in the first leg at the Etihad on 18 February.

Furthermore, Neymar's adaptation to La Liga has been smooth. He has already scored 10 goals and grabbed 12 assists in 22 games since arriving in Spain - netting five goals in his last two games for the Blaugranas.

Domestic Form: Barcelona are unbeatable at Nou Camp this season. The Catalans have won their eight La Liga games at home as well as their three Champions League games.

The Manager: Gerardo Martino has failed to convince the Spanish pundits since he took over the Catalans last summer. The problem for the Argentinian manager is not the results, but the new style that he is trying to implant in Barcelona, far from the passing game that they have played in the last few seasons under Pep Guardiola and Tito Villanova.

Martino has no previous experience in the Champions League; before his move to Barcelona he had only coached in South America, winning an Argentine League with Newell's Old Boys and making a major impact with Paraguay in 2010 World Cup.

Prediction: Alongside the tie between Arsenal and Bayern Munich, this is probably the hardest tie in the Champions League last 16. Both teams changed the manager last summer and they are still acclimatising to their new styles. Both Manuel Pellegrini and Gerardo Martino have struggled to fashion a a solid defence, leading many to predict a high-scoring tie - especially given the striking talent the two sides posses.

Barcelona's vast experience in the Champions League may be one of the keys to the tie, given City have never previously made the last 16. But equally Barcelona's side is ageing and, according to some, past its best. Both sides are much stronger at home than on the road, so any away goals will be crucial.

Barcelona have won the trophy four times, the latest in 2011, and they will face Manchester City for the first time in a competitive fixture. The most recent metting between the two sides came in 2009, during a friendly for the Joan Gamper Trophy, which City won 1-0 at the Nou Camp.