Colo Colo, Atletico Tucuman looking to cause upsets in Copa Libertadores quarterfinals

Lucas Barrios Alexandre Schneider/Getty Images

The quarterfinals kick off this week in the Copa Libertadores, South America's Champions League.

The eight teams left standing in the competition contain seven former winners -- and two outsiders. And if that comes across as a mathematical impossibility, it is easily explained.

Argentina and Brazil dominate. The rest of the continent has a sole representative, Colo Colo of Chile. The Santiago giants have one Libertadores title to their name, all the way back in 1991. Their recent record, though, is dismal. This is their 13th participation in the current century, it is only the second time they have qualified from the group phase and the first time they have reached the quarterfinals.

They scraped into the last eight by overcoming Corinthians on the away goals rule, and now they take on another huge team from Sao Paulo, the money-rich Palmeiras -- a club blessed with a deep squad and a revitalised team under the vastly experienced Luiz Felipe Scolari.

Colo Colo's coach is a relative novice -- the 40-year-old ex-Chile international Hector Tapia. The former striker has a wealth of experience to call on in his squad, perhaps too much. Colo Colo are an ageing side, with seven or eight of the usual starters over 30. Some, like talismanic striker Esteban Paredes, are aged closer to 40. The outstanding quality comes from gloriously imaginative, twinkle-toed playmaker Jorge Valdivia, now 34 -- a former club idol at Palmeiras.

Valdivia was the key figure in Colo Colo's narrow triumph over Corinthians. It is hard to imagine a team coached by Scolari giving him so much space -- and that battle in Thursday's first leg in Santiago could be crucial to the outcome. Palmeiras, whose only title came in 1999, will consider themselves strong favourites over the two legs.

Wednesday night is a real battle of the big guns. There are a total of ten titles on the table in the all-Argentine clash between Independiente and River Plate. With seven wins, Independiente are most successful side in the history of the competition. But their last trophy came in 1984. All three of River's wins have come since then.

The Argentina-Brazil clash between Boca Juniors (six titles) and Cruzeiro (two titles) would have made for a worthy final. Boca, the most successful side this century, have a deep squad while Cruzeiro, under former Brazil coach Mano Menezes, are a tough nut to crack, tight in defence with flashes of attacking brilliance -- virtues that are very useful in any cup competition.

The action kicks off on Tuesday night with another Argentina vs. Brazil contest, which features the other outsider in the last eight.

Reigning champions Gremio, seeking to become the first Brazilian club to win the title on four occasions, visit the only team in the quarterfinals who have yet to lift the trophy. Indeed, Atletico Tucuman only made their Libertadores debut last year, where they enjoyed their fair share of adventures before narrowly failing to make it out of the group stage.

This year they have done better -- and are riding high in the domestic league, too. After five rounds they lie second in the table (with the possibility of dropping to third after Monday night's games).

All of this is revolutionary. Argentine football reflects its society, with most of its main teams clustered around the capital, Buenos Aires. Tucuman is located far to the north and are the first club from the region to take part in the Libertadores.

The fans are relishing the continental experience. Both last year and this there has been a fervent atmosphere in Tucuman's stadium for the home games, and the supporters will hope that on Tuesday night they can create an environment to inspire their side and send shivers down the spine of their illustrious opponents.