Costa Rica got off the mark in this year's Copa America with a win that leaves hosts Argentina in trouble in Group A with a game to play.
The youthful Ticos scored twice after half-time as Bolivia lost their focus and had two men sent off.
Goals from Josue Martinez and the outstanding Joel Campbell were the difference, although the main talking point was the impact the win had on Argentina.
With two draws from their two games it is win or bust from their final group meeting with Costa Rica, who know a draw will be enough to take them through.
Martinez went close to opening the scoring midway through the first half when his back-post header was deflected over, before Diego Madrigal could not get his feet straight after breaking behind the Bolivia defence.
Costa Rica continued to impress after the break and they deservedly went ahead in the 59th minute when Martinez netted his second international goal.
Heiner Mora's shot was saved by Carlos Arias but the ball fell perfectly for Martinez who slotted into an open goal.
Campbell then hit the bar with a free-kick before Bolivia lost their first man in the 70th minute.
Martinez got in behind their defence and, although he failed to convert, he managed to square for Mora whose shot was goal-bound until Ronald Rivero blocked it with his arm and was dismissed.
Costa Rica got a penalty as a result, but half-time substitute Alen Guevara was denied by Arias from the spot and on the rebound.
Mora then had a goal ruled out for offside after Campbell bundled the ball to him, while Bolivia's task was made all the harder when Walter Flores was sent off for a late challenge on Guevara.
With only nine men to beat Costa Rica went for the kill and, after David Guzman had hit the post with a free-kick, Campbell finished the job when he broke through on Arias' goal.