PREVIEW-Soccer-Old rivals in a fix in the Libertadores Cup

By Brian Homewood

RIO DE JANEIRO, March 26 (Reuters) - Old rivals Gremio and Internacional both need home wins this week to stay in contention in their respective groups in the South American Libertadores Cup.

The two Brazilian teams from the southern city of Porto Alegre, both former Libertadores winners and both among the pre-tournament favourites, have struggled to get into gear.

Defending champions Internacional host Velez Sarsfield of Argentina at the Beira-Rio stadium on Wednesday while Gremio take on Colombia's Deportes Tolima at the Olimpico, around two kilometres down the road, the previous evening.

Both will be out to avenge defeats against the same opponents.

Gremio, champions in 1983 and 1995, went down to a shock 1-0 defeat against Tolima while Internacional were thumped 3-0 in their first meeting with Velez in Buenos Aires.

Gremio are second in Group Three with four points from three games, three behind Tolima and ahead of Paraguay's Cerro Porteno on goal difference. They have managed only one goal so far.

"We are going to be much better here than we were there," said coach Mario Menezes after a training session held behind closed doors on Sunday. "We need to be faster and improve our final passes."

Gremio's defenders will renew their battle with Tolima's 19-year-old striker Darwin Quintero.