Liverpool thought that they'd opened the scoring when Ben Foster spilled Glen Johnson's venomous shot into Jonjo Shelvey's path, but the easy finish was ruled out (correctly) for offside. Had Shelvey left the ball for the onrushing Jose Enrique, West Brom would have been down, but it's hard to blame a footballer for not sticking the ball in when given the chance.
It was certainly a less egregious error than the one Daniel Agger made later in the half. Presented with a perfect cross off the left boot of Stewart Downing, the unmarked centre back rose to meet the ball only for it to apparently phase straight through his head and out for a goal kick. Hilarity continued when Baggies right back Steven Reid nearly put the ball into his own net under zero pressure.
The hosts should have gone ahead shortly after halftime and it took a frantic scramble to deny Downing and Steven Gerrard as they both looked to pounce on a loose ball in the six-yard box. Jordan Henderson then had a flick well saved by Foster as Liverpool looked to grab the goal their performance merited. The finishing, however, wasn't exactly of the same calibre of their overall play, a problem Luis Suarez demonstrated magnificently when his shot from 18 yards nearly hit the corner flag.
Brendan Rodgers sent in reinforcements, bringing off both Shelvey and Henderson for Raheem Sterling and Fabio Borini. That change nearly paid off immediately when Borini's snapshot drew a smart save from Foster. The West Brom goalkeeper was tested further with a powerful drive off Gerrard's left boot, but again Liverpool were denied, and Borini contrived to poke the rebound wide from point-blank range.
The Reds wasted a gilt-edge opportunity to score when they were awarded a penalty for no apparent reason, but once more Foster kept them out, diving to his left to keep out Gerrard's low spot kick, and they were immediately punished. Pepe Reina just about managed to tip Youssof Mulumbu's 20-yard drive past the post, but from the corner the hosts left McAuley unmarked and the centre back was able to head in off the underside of the crossbar.
Lukaku had been introduced shortly before before the opener, and the young Belgian made an immediate impact. He gave notice of his intent by demolishing Jamie Carragher and Agger on a 50-yard run that ended up with a shot wide, but Liverpool failed to take heed and paid the price when he spun Agger again and unleashed an shot that Reina might have done better with as it blew through his hands and into the back of the net.
Down 2-0, five minutes of injury time suddenly looked very short indeed, and Liverpool had no hope of recovering as they saw their previously out-of-form visitors leapfrog them in the table.