Free-to-view highlights of Albion's dramatic victory at Blues.
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Charlie Austin stepped off the bench to bag a dramatic brace as Albion twice came from behind to secure a thrilling 3-2 derby victory over midlands neighbours Birmingham.
Grady Diangana's fifth goal of the season quickly cancelled out Lukas Jutkiewicz's third-minute header amid a frenetic start at a windy St Andrew's.
Blues restored their advantage just minutes after the interval courtesy of Harlee Dean's header.
But it was substitute Austin who made the decisive impact, levelling matters in the 73rd minute with a superb first-time finish from 20 yards shortly after his introduction.
And it was the in-form Baggies marksman who completed the turnaround with his sixth goal in five games to secure local bragging rights when he headed home an 81st-minute winner, sending the 2,768 travelling Albion fans into raptures.
The fiercely-contested derby triumph extends the club's unbeaten sequence to an impressive 12 matches and ensures Slaven Bilić's side return to the summit of the Sky Bet Championship.
Albion showed three changes from Wednesday's 1-1 draw at Wigan Athletic, Diangana, Matheus Pereira and Hal Robson-Kanu recalled to the starting XI.
But it was the hosts who took an early lead when Jutkiewicz headed home Maxime Colin's cross from close range.
Alvaro Gimenez went close at the near post as Blues applied early pressure, yet their lead lasted a mere seven minutes as Albion drew level.
As with the opener, it came via a recycled corner, Matt Phillips' drilled effort to the far post poked home by Diangana.
Jeremie Bela tested Johnstone with a fierce free-kick with 25 minutes on the clock, with the Baggies unable to capitalise on a promising break at the other end shortly afterwards.
Robson-Kanu nodded Phillips' cross narrowly wide before Albion suffered a blow when the lively Diangana was forced off due to injury prior to the break, replaced by Kyle Edwards.
Yet the Baggies were indebted to Johnstone on the stroke of half-time as he stood up well to deny Kristian Pedersen when he latched on to Jude Bellingham's clipped ball over the top.
In similar fashion to the first half, Blues struck just a matter of minutes into the second period when Dean headed home Bellingham's far-post corner.
Livermore swivelled and fired over when presented with a good opportunity inside the penalty area moments later.
Bilić introduced Darnell Furlong and Austin as Albion searched for a route back into the game.
And it duly came within minutes of the latter's introduction.
Austin received the ball more than 20 yards from goal, took a touch before turning and firing an unstoppable long-range strike into the top corner.
No sooner had he levelled matters than Austin secured all three points when he headed home a right-wing cross from fellow sub Furlong.
Bela headed over a good opening for the home side in the final stages, but it was Albion who held firm to extend their unbeaten sequence to seven matches against Blues.
Albion: Johnstone, Ferguson, Bartley, Ajayi, Townsend (Furlong 61), Livermore, Sawyers, Phillips (Austin 70), Pereira, Diangana (Edwards 40), Robson-Kanu.
Subs: Bond, Hegazi, Barry, Krovinović.