Colombian Gustavo Bolivar (L) and Costa Rica forward Joel Campbell (R) compete in a tight match  [EPA] 

Colombia defeated 10-man Costa Rica 1-0 on Saturday in the second match of the Copa America.

Adrian Ramos scored in the 45th minute, finally breaking through after Costa Rica's Randall Brenes was sent off in the 28th on a straight red card.

Colombia lead Group A from Bolivia and Argentina following their 1-1 draw on Friday in the tournament opener. Costa Rica, playing as a guest team in the South American championship, are without a point and fielding a youth team, as are Mexico.

"To start with a victory always gives you confidence," Ramos said.

"It wasn't a clear victory, but the important thing is that we won."

Colombia were unimpressive, seldom dominating a short-handed team featuring mostly young, inexperienced players. Colombia could get a shock when they face Argentina on Wednesday with the Gauchos under pressure at home after a disappointing opening match.

Brenes was sent off after a hard tackle, but Colombia struggled to take advantage.

Ramos broke through on an individual effort. Taking a through pass, he raced into the area and then dribbled around Costa Rica goalkeeper Leonel Moreira before slotting home from short range.

Colombia star forward Falcao Garcia seldom had the ball in position to strike and went off in the 77th.

Colombia coach Hernan Dario Gomez said this week he would resign if the team failed to reach the quarter-finals. Despite a poor game, the victory was a big step for Colombia to reach the second round.

Two-time defending champions Brazil play on Sunday in Group B against Venezuela, and Paraguay face Ecuador.

Brazil have won four of the last five titles, and defeated Argentina in the last two finals.

Source: Agencies