Ayrton Costa scored in the first half as Boca Juniors advanced to the semifinals of Argentina's Primera Division Clausura tournament on Sunday with a 1-0 home win over Argentinos Juniors.

The hosts took the lead in the fifth minute of the quarterfinal clash when Costa struck from close range after Miguel Merentiel's volley was parried away by goalkeeper Gonzalo Siri.

The visitors controlled 72 percent of the possession and posed a constant threat in attack but were repeatedly denied by Boca goalkeeper Agustin Marchesin, who made five saves.

"We were far superior from the opening whistle," Costa said after the match. "In the first half I think we deserved to score at least three goals. They had more of the ball, but we were the better side throughout the 90 minutes and deserved the victory."

The result at La Bombonera means Boca will meet the winner of Monday's quarterfinal between Racing and Tigre for a place in the final.