1) Sergio Agüero - Argentina
Despite only starting one game so far, Agüero is the tournament's top-scorer with three goals. His late equaliser against Bolivia saved Argentina's blushes in the opening game and he set the course for a confidence-boosting win over Costa Rica with a predator's finish right on half time. There's no doubting Agüero's class, and now I've worked out how to do the ü in his name, expect to be hearing a lot more about him.
2) Tomás Rincón - Venezuela
Playing for Hamburg in the Bundesliga, Rincón is one of several players in the current Venezuela team to have made the move to Europe. For the national side he is a commanding presence, and their unlikely qualification from Group B has been built on his strong midfield performances. With Rincón breaking up play in the centre, Venezuela held Brazil to a nil-nil draw and they'll be hoping he can keep Chile quiet on Sunday.
3) Radamel Falcao - Colombia
Falcao has been prolific for Porto this season and Colombia are pinning their hopes on him at the Copa America. His two goals both came in the last group match against Bolivia, and they were just reward for his tireless work ethic. Falcao's willingness to make incisive runs created numerous chances for Colombia when they played Argentina, and he'll no doubt fancy a re-match in the semi-finals. Expect him to put Peru out on Saturday.
4) Gary Medel - Chile
Although the least glamorous of Chile's team, the 'pitbull' has been their most important player so far. Not only can he time a tackle to perfection, he's also great at picking a pass to start an attack. With Chile looking on the ropes against Peru in their last group game, on came Medel to sure up the midfield. Ten minutes later, La Roja scored the winner to top the group. He's the difference between Chile being able to play their expansive flowing football and falling to pieces. If I were Neymar, I'd be fearing a match up in the semis.
5) Joel Campbell - Costa Rica
Campbell only earned his first cap for Costa Rica in June, and he hasn't looked back since. His darting runs, calm finishing and hunger for the ball make him the Central Americans' most exciting propsect since Paulo Wanchope. The ninteen year old embarrassed an experienced Bolivian defence in one of the most entertaining games of the group stage and although he now finds himself on a plane home, it surely won't be long until he's leaving Costa Rica again, with Sunderland amongst the clubs linked to his signature.