The hosts started confidently as Yeremy Pino shot on target inside 40 seconds, but Leganes soon began knocking the ball around nicely and perhaps ought to have gone ahead on 13 minutes when Seydouba Cisse fired wide from a promising position.
The visitors had most of the possession in the game’s first quarter, but their failure to make the most of it was punished when a neat passing sequence culminated in Alex Baena finding Pape Gueye, whose cutback was struck at goal by Alfonso Pedraza, with Ayoze Perez altering the ball’s trajectory with a clever flick past Marko Dmitrovic to give Villarreal the lead.
Now in the ascendancy, the Yellow Submarine needed just eight minutes to double their advantage.
Juan Foyth’s punchy pass found Pino in acres of space, and the 22-year-old scampered forward before slipping in Perez, who steadied himself under pressure from Adria Altimira to finish with aplomb for his 21st goal of the campaign in all competitions.
Not content with their two-goal lead, Villarreal looked hungry for at least one more goal before half-time, and after a couple of chances went begging, they got their third just before the break.
Baena’s gorgeous pass with the outside of his right boot stopped in front of Nicolas Pepe, who stroked the ball home to put the game beyond the hapless visitors.
To their credit, Borja Jimenez’s side did not allow their heads to drop, but they continued to find it difficult to create consistent, clear-cut opportunities.
Pino was guilty of letting them off the hook for further damage after being found completely on his own by the perceptive Perez’s square pass.
Even after a quadruple substitution just after the hour mark, Leganes failed to worry the Villarreal defence on too many occasions, with their best chance seeing Jorge Saenz hit the crossbar with a header following a corner.
Villarreal have now won four straight league matches for the first time since March last year, and will therefore travel to league leaders Barcelona on Saturday full of confidence.
Leganes, meanwhile, remain 18th, but are four points adrift of safety after Deportivo Alaves’ 1-0 win over Valencia, though their survival hopes are boosted by the fact their final two matches are against the two sides beneath them in the standings.
Flashscore Man of the Match: Juan Foyth (Villarreal)