On paper, this trip to fortress Hawthorns always looked a major test of Manchester City's title credentials.
So it proved, as Edin Dzeko came off the bench and rescued victory from the jaws of defeat for Roberto Mancini's 10-man team in the most dramatic of circumstances.
Shane Long's poacher's goal had given West Brom a 67th minute lead and looked like propelling the home side to their fifth consecutive home Premier League win of the season following James Milner's early sending-off.
But Dzeko had other ideas. A minute after coming on the pitch, he headed an 80th minute equaliser from Carlos Tevez's free-kick following an error from Ben Foster.
|EDIN TO THE RESCUE
|HOW DZEKO RATED VS READING
|Given 12 minutes to make an impact, he needed just two, directing Nasri's curling delivery over the floundering Foster. Then, in the dying moments, he calmly stroked home the winner. Maybe he should start next time?|
Either side of Dzeko's last-minute winner, another substitute, Romelu Lukaku, had come close to scoring, but he was denied - first by Joe Hart and then by an Aleksandar Kolarov goal-line clearance.
Before kick-off this clash had 'upset' written all over it. West Brom have adapted smoothly following the change-over from Roy Hodgson to Steve Clarke, accumulating 14 points from their first seven matches.
Moreover, the Hawthorns has been quite a fortress for Clarke's team. Their opening four home league matches have yielded four victories - against Liverpool, Everton, Reading and QPR – and nine goals.
Mancini selected a team with a strong English core. Joe Hart, Joleon Lescott and Milner all started despite the 20-hour delay to England's match against Poland in midweek and they were complemented by Gareth Barry and Micah Richards.
Sadly for City, Milner only lasted 23 minutes. A mistake by Vincent Kompany allowed Long a clear run on Hart's goal, which meant that the midfielder had to time his tackle perfectly. He did not.
Long was hacked to the ground and replays showed that Mark Clattenburg was correct to show Milner a straight red card for a professional foul.
Briefly, City lost their composure as feisty challenges rained in from the home side, backed by their vocal home support.
Mancini needed his 10 men to stand firm but Balotelli was having one of those days when he felt the whole world was against him. After being booked in the 19th minute for lashing out following a challenge, he began to tread a disciplinary tight-rope as the opening half finished, even if he was harshly penalised for a foul.
When the whistle blew and with the crowd increasingly getting on his back, Balotelli marched up to Clattenburg and his assistants to have his say, before being sensibly escorted away by Hart.
Few among the 24,891 spectators expected the temperamental Italian to come back out after the break, but Mancini re-shaped his team into a 4-3-1-1 formation, moved Tevez back and gave Balotelli the spearhead role in which he is far more comfortable.
It paid immediate dividends. City began to gain a foothold in the match, creating opportunities and quietening the home fans for the first time.
Tevez's long-range shot was heading for the top corner before it was athletically pawed away by Foster while Toure headed over the bar after Balotelli's mis-hit volley.
Against the run of play, West Brom took the lead after 67 minutes. Substitute Peter Odemwingie made an immediate impact, putting Long through on goal with a slide-rule pass and the No.9 tapped in his third league goal of the season and fifth in all. Replays showed he was narrowly on-side as City’s defenders moved forward.
Mancini hauled off Barry and sent on Dzeko to rescue a point. The Bosnian managed to do even better.