A cracker of a contest is expected when second-placed Chennaiyin FC take on fourth-placed FC Pune City at the Jawaharlal Nehru Stadium in Chennai on Wednesday. The hosts have a chance of topping the group if they win by a margin big enough to displace league leaders Atlético de Kolkata who currently lead Chennaiyin by three points and two goals. On the other hand, a victory for Pune City would see them leapfrog Chennaiyin and move into second spot.The two sides come into this fixture on the back of goalless draws. They were inseparable when they met in the first leg, playing out a 1-1 draw. Pune City have found a rich vein of form of late, but the unfortunate injury to forward John Goossens was a tough pill to swallow for Franco Colomba’s men. They will be looking to put that behind them and bash on regardless.Chennaiyin have netted the most goals in the competition, 14, as compared to Pune’s eight. The home side’s rampaging attack has taken more shots (102-85) and shots on goal (54-41) than the visitors. The problem for Chennai is their propensity to concede goals despite having the best defence in the league on paper. They have kept just one clean sheet in the tournament, while Pune have four. Arindam Bhattacharya has been brilliant in goal for Pune and he will look to keep his good form running.Key BattlesJohn Stiven Mendoza vs Bruno CirilloThe young Colombian forward is creating waves in the ISL with his trickery and pace. Chennai will pin their hopes on him yet again to provide the breakthrough. Italian defender Bruno Cirillo is one of the major reasons why Pune have kept four clean sheets. The tough-tackling, no-nonsense defender has been a rock and will look to contain the threat from the diminutive forward.Marco Materazzi vs Kostas KatsouranisThe Italian World Cup winner shoulders the dual responsibility of being coach and player, and despite being a central defender by trade, has eased into the defensive midfield position for Chennaiyin with great success. He will be up against roving 2014 Greek World Cupper Kostas Katsouranis, who is having an impressive run for Pune and is blessed with the ability to shoot devastatingly from distance.Gouramangi Singh vs Dudu OmagbemiThe experienced Indian defender has had a good outing in the illustrious Chennai backline, though they have managed just one clean sheet. His willingness to tackle and give chase makes him a valuable asset to the team. He will be up against the in-form Nigerian striker whose introduction in place of David Trezeguet has galvanised the visiting team. The strongly built Dudu is able to bully defenders off the ball and is also dangerous from set pieces. Gouramangi and the rest of the Chennaiyin defence will have to keep him on a tight leash.Players to watchChennaiyin FCElano Blumer – The Brazilian's remarkable run of scoring in each of the first seven games came to an end in Chennai's last game. However, he is by far the league's top scorer, with eight goals. Elano is the youngest of the eight marquee players and his fitness levels and class have helped him stamp his authority on the tournament with his free kicks and passing ability. The Pune defence will be on its toes for the 90 minutes to contain the threat posed by the former Manchester City man.FC Pune CityArindam Bhattacharya – The Bengali goalkeeper has been a revelation for his side after he replaced an injured Emanuele Belardi. His quick reflexes and speed off the blocks make it difficult to get the ball past him. The Indian will rely on these assets to keep the incredible Chennai strike force at bay.Team Speak:Chennaiyin FCMarco Materazzi (player-head coach): We will try to play our best and get maximum points.FC Pune CityFranco Colomba (head coach): Football is a sport in which you need one goal to win. But, it’s not easy to score.