Bolivar momentarily went four points clear with a 2-0 road win over cellar-dwellers Universitario Cobija, and were on the verge of a handy buffer before Oriente struck late to earn a 1-0 win over San Jose.
Gualberto Mojica's 83rd-minute goal brought Oriente back to within a point of Bolivar, with two matchdays remaining.
League-leading goalscorer Juanmi Callejon (14 goals) took less than four minutes to register the opener in Cobija.
Bolivar maintained their buffer throughout, and sealed the points in second-half injury time when Nelson Cabrera scored.
The Strongest flexed their muscle late to crush Petrolero Yacuiba 4-0, the home side scoring three times in nine minutes to record a resounding victory.
Ernesto Cristaldo scored a brace for the third-placed outfit.
The top three were the only sides to win at the weekend, with three score draws played out.
Real Potosi fought back twice to earn a 2-2 stalemate at home to rivals Nacional Potosi, Wilstermann scored first at home but were pegged back in a 1-1 draw to Blooming, while Sport Boys and Club Universitario shared the spoils 1-1.
