by Marc Serber

The first leg matches of the Copa Sudamericana Round of 16 continues on Wednesday with two very intriguing encounters.

In the early match, Universidad Catolica welcomes Velez Sarsfield in the third meeting between the two clubs this year. They met twice in the group stages of the Copa Libertadores and played one of the tournament’s most exciting matches with Catolica coming from 3-1 down to win 4-3.

Universidad Catolica lost some of its best players in the winter transfer window with Argentines Lucas Pratto (Genoa), Marcelo Canete (Sao Paulo) and Tomas Costa (CA Colon) all moving on.

Despite the losses, Los Cruzados remain one of Chile’s most talented squads with captain and playmaker Milovan Mirosevic leading the charge. Another mainstay, Jorge Ormeno is an excellent shield in front of the back four, while young striker Felipe Guiterrez has a promising future at both the club and international level.

Velez has been lauded for being one of the few squads in South America to hold on to the majority of its best players. The club from the Liniers neighborhood of Buenos Aires was duly rewarded with the 2011 Argentine Clausura title and was just a penalty miss away from advancing to the final of the Copa Libertadores.

Santiago “The Tank” Silva and Juan Manuel “The Small Donkey” Martinez provide a perfect juxtaposition – as their nicknames suggest – with Martinez’s skill and guile in the attack complementing Silva’s power.

If Velez travels to the Chilean capital looking to attack, than an open and exciting game may very well be in the cards. If the Argentines look to close the game down with the intent of taking care of business in the second leg back in Liniers, then there is the sad possibility that these two sides might just cancel each other out.

In the late match, Bolivia’s Aurora hosts Brazilian side Vasco Da Gama at an altitude of more than 2,500 meters in the city of Cochabamba.

For the Brazilians, there is a possible recipe for disaster. Aurora is currently at the height of its powers. “The People’s Team” as Aurora is known is not only first in Bolivia, but played some exhilarating attacking soccer in both legs of their previous round. A 6-3 aggregate dismantling of Paraguay’s Nacional.

In addition, Brazilian teams do not usually fare well in the altitudes of Bolivia and often play for a result that allows them to take care of business at sea level in front of their home fans. With this in mind coupled with the fact that Vasco Da Gama lie in first place in the Campeonato Brasileiro, but have a bunch of teams breathing right down their necks, interim head coach Cristovao Borges is taking only 15 players to Bolivia. Most of them aren’t even first team regulars.

Even with the small and hardly match-tested squad, it is important to remember that the top Brazilian teams are like the New York Yankees. Their bench can usually beat most of the other challengers’ best XI.

Trying their luck against an in-form Aurora in the heights of Cochabamba might just be too big of a gamble for Vasco Da Gama, however, and a shock upset could very well be in the making.

Both matches can be seen on Fox Deportes in Spanish and English with the SAP option. Coverage starts at 6:00 PM Eastern Time.

** You can follow Marc Serber on twitter@SoccerSerber