It took the visitors just seven minutes to break the deadlock as Paco Alcacer evaded several challenges to fire in the opening goal.
Alcacer was involved in the second goal as well, playing the ball in for Andre de Gomes to drive in low, increasing Valencia's lead inside the opening 20 minutes.
Lafita continued to look the home side's best chance of getting a goal back before the break as he forced another stop from Alves, before another long-range effort failed to trouble the keeper.
Sofiane Feghouli came off the bench early in the second half and was immediately involved when he was tripped in the penalty area, giving the visitors a spot kick.
Rodrigo clinically dispatched the penalty to seemingly put the result beyond doubt, but immediately gave Getafe hope as he committed a foul during the kickoff, earning him his second booking of the game.
Despite facing just 10 men for the final 25 minutes, Getafe created little in a bid to get back into contention late on, allowing Valencia to see out a comfortable victory.
The result moves Valencia up to second in the table, two points behind leaders Barcelona, while Getafe sit 16th.