Uruguay were already leading 1-0 from a sixth minute Nicolas Lodeiro goal when Jose Quintero was shown a VAR-assisted red card for throwing an arm in an aerial challenge.
The 23rd minute sending off put Uruguay firmly in the driving seat and Edinson Cavani with an acrobatic volley and Luis Suarez with a poacher’s goal made it 3-0 by half-time.
The Uruguayans took their foot off the pedal in an uneventful second half but an own goal from Arturo Mina 12 minutes from time, confirmed by VAR, sealed a miserable night for Ecuador.
The result puts Uruguay top of Group C, with Japan to play Chile in the other group game tomorrow.
Asian champions Qatar hit back from 2-0 down to earn a 2-2 draw with Paraguay at the Copa America on Sunday (Jun 16).
An Oscar Cardozo penalty and a stunning Denis Gonzalez strike gave the South Americans a 2-0 lead in Rio de Janeiro but goals from Almoez Ali and Boualem Khoukhi in the final quarter snatched a share of the Group B spoils for the tournament debutants.