By Richard Dayus
West Brom maintained their unbeaten start to the season, despite twice falling behind before hitting three second half goals to send them up to fourth in the league.
Lewis O'Brien gave the bottom side the lead only for Matt Phillips to equalise three minutes later, following some excellent work from Darnell Furlong down the right.
Karlan Grant put the Terriers back in front just after the half hour mark after Albion once again failed in playing out from the back, Bartley giving the ball away cheaply and Huddersfield taking full advantage, finishing with Grant slotting past Johnstone into the corner.
Bilic made a half time change with Grady Diangana replacing the ineffectual Filip Krovinovic with Metheus Pereira moving into a more central position.
The change gave Albion a fresh impetus and their wave of pressure finally told in the 70th minute, the excellent Darnell Furlong rising at the near post to nod in Diangana's cross.
Four minutes later and Diangana was at the heart of things again, this time beating a handful of Huddersfield defenders with a mazy run before cutting back for Phillips to side foot home his second of the game.
Albion controlled the game from then and finally added to their lead a minute from time, Semi Ajayi rising unmarked at the far post and directing a header into the bottom corner.
West Brom have now earned themselves 15 points from losing positions this season, having gone behind in 7 of their 8 league games. Once again, this side have shown good character to come back from a goal down but Bilic will want his side to cut out the sloppy mistakes that have led them to chase the majority of games they have been involved in this season.