A 22nd minute goal from defender Diego Lugano secured the win for Uruguay, who finished fifth in South American qualifying and had to play-off with Costa Rica from the CONCACAF region for a place in South Africa next June.
Costa Rica's task of turning the game around was made harder after Randall Azofeifa was sent off in the 53rd minute for a second yellow card but despite plenty of second half possession they rarely threatened an equaliser.
Uruguay, two-times World Cup winners, went into the game strong favourites but in the knowledge the artificial surface and hostile crowd at the Saprissa have made the venue one of the toughest in Central America for visiting teams.
But it was the home side who appeared to be most affected by the atmosphere as they made a nervy start and fell behind to Lugano's goal.
After Diego Forlan went close for Uruguay, central defender Lugano made the breakthrough, heading a corner across a crowded penalty area and when the Costa Rica defence failed to clear, he pounced to hook the ball home.
It was not until shortly before the interval that the home side created a real chance when the dangerous Brian Ruiz flicked a header just over the bar after a long ball forward from Walter Centeno.
Costa Rica's Brazilian coach Rene Simoes will surely have spent the interval urging his side to get more combative in midfield as too often in the opening 45 minutes they were pushed off the ball by an aggressive Uruguay.
But it was the wrong kind of aggression from Azofeifa that left Costa Rica a man short after he was sent off following a reckless challenge that earned his second yellow card.
Oddly, with the numerical disadvantage, Costa Rica looked more threatening and went close through substitute Rolando Fonseca whose low cross was turned just over the bar by Lugano.
Uruguay appeared content with a single goal victory away from home, with their second half attacks mostly restricted to counter attacks with the wily Forlan.
They will now expect to book their place in South Africa in front of a packed Centenario stadium in Montevideo on Wednesday.
