The Iron had the better of the early exchanges. Yann Songo’o made inroads with Kgosi Ntlhe down the left wing. The latter rounded Sam Johnstone in the Albion goal but there was no claret and blue shirt in the penalty area to convert the chipped cross.
Songo’o fashioned another opening as the midfielder surged down the right flank this time. His delivery found Adam Hammill in the box but the winger’s header floated over the post.
Albion’s Matty Phillips tried his luck from the edge of the area with 15 minutes on the clock, but his shot fizzed narrowly over the bar.
The visitors failed to clear Hammill’s set-piece which fell to Oluflela Olomola but the striker couldn’t make the most of the opening, with his low effort just off target.
Rory Watson was called into action on the hour mark. Filip Krovinovic and Phillips combined for the Baggies but the Iron shot-stopper got down well to deny the Scotsman, eventually scooping up the ball and averting the danger.
The Iron held their own against the strong Championship outfit in the first half but the visitors flew out of the blocks after the break, netting three times in four minutes.
Shortly after the restart, the Baggies broke the deadlock. Phillips volleyed the visitors in front to make it 1-0.
Albion found their rhythm and it wasn’t long before they doubled the advantage. Krovinovik toe-poked the ball under Watson’s body and the visitors lead 2-0.
Phillips notched his second and the Baggies’ third, nodding in from close range to make it 3-0 to West Brom.
Hammill continued to impress for the Iron, going close with a free-kick around 20 yards from goal, won by Alex Gilliead. Johnstone was alert to palm the powerful set-piece to safety.
Substitute Jordan Hallam also came close, as he flashed a powerful effort past the post from 20 yards.
The Baggies glossed the scoreline with a fourth. Iron old boy and skipper for the day Conor Townsend set up substitute Hal Robson-Kanu to make it 4-0 late in the day.
IRON: Watson, Ntlhe (Butroid 68), Songo’o (Lund 68), Horsfield, van Veen, Hammill, Perch, Gilliead, Olomola (Dales 68), McGahey, McAtee (Hallam 60).
Substitutes not used: Eastwood, Burgess.
West Bromwich Albion: Johnstone, Bartley (Robson-Kanu 60), Krovinovic (Ajayi 60), Livermore (Zohore 60), Phillips (Brunt 60), Townsend (Melbourne 84), Burke (Leko 60), Edwards (Tulloch 68), O’Shea (Wilson 84), Field (Harper 60), Ferguson (Fitzwater 84).
Substitute not used: Bond.
Attendance: 1,956.