Aleksandar Mitrovic opened the scoring from the spot after 20 minutes following a dubious penalty decision from referee Michael Salisbury.
The Baggies failed to click into gear as last week's man of the match Robert Snodgrass played a stray ball back towards goalkeeper Sam Johnstone only to be intercepted by Mitrovic who added his second of the afternoon.
The on-form Serbian striker then picked up his 18th goal of the season, a great move slicing through the Baggies' defence to take home the match-ball.
Tosin Adarabioyo was then given his marching orders as Salisbury handed out his second red-card this time to the Cottagers defender for a late challenge on substitute Grady Diangana.
Mitrovic on fire
The Serb hit his 18th goal of the season, and the Championship top scorer showed exactly why he is that.
Although the second goal was gifted to him by Snodgrass, the penalty was calmly dispatched and practically unstoppable.
His third finish was a prime example of the striker's excellent movement, peeling away from the West Brom defence to create space, allowing Wilson to have clear sight for the pass into him.
The 27-year-old has scored more goals than ten second-tier sides this season, and if he continues with this rate of scoring he will notch up 49 goals by the end of the campaign - simply sublime.
Mistakes in the Baggies’ back-line
The Albion defence conceded three, but it certainly could've been a higher score for the Cottagers.
Most of the time, the Baggies were the architects of their downfall, with several errors leading to chances being created for Fulham.
Of course, the Snodgrass mistake is the most noticeable one as it directly resulted in a goal for the hosts, however, several blunders from the West Brom defence went unpunished.
Matt Clarke took a quick free-kick just outside his 18-yard box only to pass the ball sideways, seemingly aiming for Johnstone, but inadvertently played in Fulham winger Neeskens Kebano who raced through only to place his shot wide of the target.
Additionally, although wing-back Furlong was seen in the replays to have played the ball after being sent off.
Contrasts in quality
Saturday's game showed a complete difference in quality and cutting edge between the two teams.
Fulham's attacks were finished off by Mitrovic as they punished Albion's mistakes, the incisive nature of the Cottagers’ front four proved to be a big difference, especially for their third goal.
A prime example of the Baggies' lack of quality in the attack came when Jake Livermore stormed forward to hassle the ball from captain Tim Ream.
Livermore found himself in a great position, only to be abandoned by the rest of the Albion team and forced to shoot straight at a defender.
The Baggies midfield couldn't get near the Cottagers pairing of Harrison Reed and Jean-Michael Seri who exemplified a double-pivot perfectly something that Snodgrass and Livermore could take a lesson from.