John Obi Mikel has often got the better of Mascherano at club level for Chelsea, and he will need to do the same if the Super Eagles are to progress.
John Obi Mikel v Javier Mascherano
Nigeria fans are often confused as to why John Obi Mikel doesn't play further forward when he features for Chelsea, as he is seen as the Super Eagles' number 10 player. That contrast of opinion is fair, but when he plays Argentina, he is likely to be forced to protect his back four from Argentina's superb attacking threats. He has had a lot of experience with his club in protecting the back four and on the whole, done a good job there. Argentina are likely to see a lot of the ball, and Mikel will be key in preventing his defence being exposed from the Argentina attack.
Javier Mascherano, like Mikel, plays a different role for his country than he does for his club. In recent years, Mascherano has played centre-back for Barcelona, but when he plays for the Sky Blues, he plays in his preferred defensive midfielder position. He was superb against Iran as he done the work that allows the many forward thinking players in his squad to attack, especially Zabaleta and Rojo in the full back area. Mascherano covers these two positions when they go forward, and thus is vital in ensuring Argentina aren't exposed on the counter attack.
The two experienced midfielders have faced each other a lot, so will know one another well, but it is sure to be an important battle in how the match is won and lost.
Emmanuel Emenike v Ezequiel Garay
Emenike played brilliantly against Bosnia & Herzegovina as he utilised his pace to expose the shortcomings in the Bosnia defence. With Nigeria likely to play on the counter attack again, a style that suits their squad, his pace on the break is an important weapon for the African side. He will need to continue his good form if he is to get the better of an Argentina back four, as you expect Nigeria to see little of the ball in the attacking areas on Wednesday.
Ezequiel Garay struggled against an Iran team that was supposed to bring little attacking threat to the World Cup. His lack of pace was exposed by Charlton Athletic striker Reza Ghoochannejhad, and thus Emenike will be looking at utilising that weakness with the aim of isolating the defender. If the Nigerian can do that, they might find some joy once again. Argentina will need to protect Garay from Emenike's pace for sure.
Kenneth Omeruo v Lionel Messi
Omeruo is one of many players who was out on loan from Chelsea last season, with his chosen club Middlesbrough in the championship. It is quite a jump to take, from the English second division to the World Cup, but his first two performances have warranted two clean sheets and thus showed he is capable of playing at the highest level, and no doubt Jose Mourinho and Chelsea will be interested in how he does.
In saying that, he is likely to mark the best player in the world on Wednesday, Lionel Messi. The Argentina captain has scored two individual goals that have been of the highest quality, and showed to everyone he is desperate to perform at his best in the World Cup and add that trophy to his long list of achievements. There is a chance Argentina manager Alejandro Sabella could rest him, with the last 16 in mind, but Messi will be desperate to play, and it will be hard not to when he is in the form he is in.
This will be the biggest challenge in Omeruo's young career to date, and the Super Eagles will be praying he can stop Messi's brilliance.