Goals from Jonas Oliveira and Roberto Soldado in four first-half minutes, the latter from the penalty spot, put the Spanish side on top at the Mestalla.
And Sofiane Feghouli's second-half brace sealed victory as BATE threatened a comeback through star man Renan Bressan and Dmitri Mozolevski.
The win takes Valencia to nine points from four games, though they remain second behind Bayern Munich having lost 2-1 at the Allianz Arena in September.
Egor Filipenko blocked Jonas Oliveira's early shot and Feghouli was similarly denied by Artem Radkov.
Keeper Andrey Gorbunov held Soldado's shot before BATE threatened for the first time, Bressan's long-range shot blocked by Ricardo Costa.
Tino Costa fired wide for Valencia but when the breakthrough came, it was emphatic.
First Jonas thrashed home Tino Costa's pass to open the scoring and then three minutes later, Denis Polyakov fouled Andres Guardado in the area and Soldado tucked away the resulting penalty.
Vitaly Rodionov denied Feghouli from Tino Costa's corner and defender Adil Rami hammered wide from long range.
Bressan was responsible for almost all of BATE's attacking efforts in the first half and had two long-range efforts saved, the first a free-kick, before a third strike flew wide.
Feghouli's lob dropped wide before Gorbunov saved Jonas' stoppage-time header.
Tino Costa fired a free-kick over the bar early in the second half before Feghouli made it 3-0, finishing from the edge of the box after he was set up by Fernando Gago.
BATE pulled a goal back, inevitably through Bressan as he swung in a free-kick from the left which curled directly into the bottom corner of the net.
Ricardo Costa missed from close range before Valencia keeper Vicente Guaita saved from Bressan and Rodionov at the other end.
A tense finish was in prospect when Rodionov teed up Mozolevski to cut the deficit to a single goal with seven minutes remaining, the Belarusian side finally showing the form which had brought them opening wins over Lille and Bayern.
But Valencia quickly responded, Nelson Valdez shooting wide before Ever Banega set up Feghouli to make the game safe in the 86th minute.