The 50th Copa Libertadores de America gets under waythis week with the first legs of six first-round matches. As well as becoming continental kings, the winners will also earn a place at the FIFA Club World Cup 2009, to be held in the United Arab Emirates in December.

The winners of the six two-leg ties that make up the first round will go forward to the group phase, where they will join 26 other teams in eight round-robin groups. The top two sides in each group then advance to the knockout rounds, which consist of two-legged home and away ties right through to the final.

Reigning champions Liga Deportiva Universitaria de Quito, who finished runners-up in last year's FIFA Club World Cup, begin their title defence in the group phase, where they will be joined by two of last season's semi-finalists, Boca Juniors and America of Mexico. However, Brazil's Fluminense, the side Liga de Quito beat to win the title, failed to qualify for this year's competition.

With the race to decide the 2009 champions about to begin, looks ahead to the week's opening matches in the first round.

A trio of champions
After a three-year absence, Penarol of Uruguay make their return to the competition on Wednesday with an awkward trip to Colombia to face Independiente Medellin. The Montevideo side were the first winners of the tournament back in 1960 and have lifted the trophy five times in all, making them the third most successful team in Copa history behind the Argentinian duo of Boca Juniors and Independiente, six and seven-time winners respectively.

Penarol have also appeared in the competition 37 times, more than any other team on the continent, and their new coach Julio Ribas feels his side can make it title number six this year: "Winning the Copa isn't impossible. We have to believe it, want it and dream of it."

After being knocked out by Liga last year, three-time champions Estudiantes de La Plata will make another attempt to recapture a trophy they last held aloft in 1970. Led by Juan Sebastian Veron, the Pincharratas will first of all have to knock out Peru's Sporting Cristal, who are making their 27th Copa appearance, a national record. "They've got a lot of new players and that's going to make it difficult because we don't know exactly what we're up against. Even so, we've got confidence in ourselves," said Estudiantes coach Leonardo Astrada ahead of Thursday's game.

Palmeiras entertain Real Potosi of Bolivia on the same day. The Sao Paulo outfit, who won the trophy in 1999 - their only success in four finals - are firm favourites going into the tie, particularly with the recent incorporation of the experienced Edmilson. The Bolivians have qualified for the Copa for the third year running and will need a good result in Brazil if they are to make headway this year.

The remaining three ties look too close to call. Universidad de Chile take on Pachuca in Santiago on Wednesday, with the Chileans looking to make the most of the Mexican side's injury problems; Argentinian duo Christian Gimenez and Gabriel Caballero are both out for the Tuzos.

In Quito, meanwhile, El Nacional are full of confidence ahead of the visit of Paraguay's Nacional, having now qualified for the Copa 22 times in all, more than any other Ecuadorian side. "The most important thing for us is to win the first leg," said home boss Jorge Celico.

El Nacional's domestic rivals Deportivo Cuenca also have to negotiate the first round. They take on Venezuelan debutants Deportivo Anzoategui on Thursday. The only other new boys this year are San Luis of Mexico, who will make their bow in the next round, some 12 years after Mexican sides were first admitted to the competition.

This week's fixtures
Tuesday 27
El Nacional (ECU) - Nacional (PAR)

Wednesday 28
Independiente Medellin (COL) - Penarol (URU)
Universidad de Chile (CHI) - Pachuca (MEX)

Thursday 29
Sporting Cristal (PER) - Estudiantes (ARG)
Deportivo Anzoategui (VEN) - Deportivo Cuenca (ECU)
Palmeiras (BRA) - Real Potosi (BOL)