Two goals in either half was enough to see the hosts claim the victory as a Ruel Sotiriou effort cleared off the line late in the second-half was the closest chance for the O’s at the Hawthorns.
Youth Team Coach Danny Webb made two changes to the side that defeated Northampton on the weekend.
Defender Toby Stevenson and striker Sam Dalby were reintroduced to the team in place of Shadrach Ogie and Lawrence Hammond who both started in the Cobblers win.
Orient got the game underway under the lights at the Hawthorns but conceded after two minutes. Heavy pressure from West Brom meant Nick Clayton-Phillips smashed home from close range after a drilled cross found him inside the box.
As the O’s began to grow in to the game, Toby Stevenson’s whipped cross was palmed in to the path of Jaedon Phillips at the back post, the winger then took a touch to set himself but saw his shot blocked before it reached Adam Przybeck in the Baggies net.
Again, Charles Clayden and Stevenson linked up well down the left-hand side and the latter drilled the ball across the face of goal but couldn’t pick anyone in red out to tap home.
The Baggies doubled their lead after 25 minutes when Clayton-Phillips slotted the ball in to the net from close range again from a cross.
Smart work from Ruel Sotiriou on the right wing allowed the striker to enter the box and drag the ball back to Clayden who waited in the middle, but the winger wasn’t able to get a clean enough connection with the ball to direct it goal wards.
Again, Sotiriou’s footwork saw him carry the ball in to the centre of the field before finding Clayden whose drag back from wide was met by the blocked shot of Phillips
The hosts furthered their lead two minutes after the restart when Finn Azaz found Rayhaan Tulloch who poked home from six yards out.
A combination of great defending from Stevenson and goalkeeping from Arthur Janata kept out Tulloch’s rebounded attempt.
Janata again did well to deny the Baggies when Clayton-Phillips looked to grab his third when he took aim from range.
Sotiriou had an excellent headed effort cleared off the line by Baggies skipper Sam Wilding after Stevenson brilliantly found the striker at the far post.
Brave defending saw Andrew Camilo-Tayca throw his body to block the shot of Azaz who worked his way in to the Orient penalty area.
Tulloch then notched his second of the evening when he smashed home a loose ball just six yards out from goal as the O’s FA Youth Cup run came to an end.
WEST BROM: Adam Przybeck, Adam Soleman, George Harmon, Sam Wilding (C), Nathan Ferguson, Kevin Healy, Rayhaan Tulloch, Zac Brown (Myles Hall 80), Callum Morton (Jacob Wakeling 86), Finn Azaz (Jamie Soule 83), Nick Clayton-Phillips
SUBS: Jack McCourt, Ted Cann
GOALS: Clayton-Phillips (2 & 25), Tulloch (48 & 86)
ORIENT: Arthur Janata, Andrew Camilo-Tayaca, Teddy Perkins ©, Mason Hall, Toby Stevenson, Charles Clayden (Eric Lopes 78), Ernold Haxhiu, Hector Kyprianou, Jaedon Phillips (Amin Benyoucef 53), Sam Dalby (Brendon Shabani 72), Ruel Sotiriou
SUBS: Samuel Amedu, Luca Carter-Henry
REFEREE: Jon Kenny