Liverpool were then left stunned by five second-half minutes which began with a red card for Daniel Agger after he was deemed to have bundled over Shane Long when the home side's striker went through on goal.
The No. 9 took the resulting spot-kick himself, but was thwarted by Pepe Reina. However, the Reds' custodian could not keep out a second West Brom penalty on 63 minutes which Peter Odemwingie drilled into the back of the net after Martin Skrtel was adjudged to have brought down Long.
And the Reds' afternoon went from bad to worse when Romelu Lukaku headed in a third for West Brom late on to secure all three points.
The pre-match team news confirmed starts for summer signings Joe Allen and Fabio Borini, while Glen Johnson began at left-back as a slight knock sustained in training prevented Jose Enrique from travelling to the Midlands.
Meanwhile, Steven Gerrard captained the Reds for the 250th time in the Barclays Premier League.
It was not just a landmark afternoon for the skipper, with Brendan Rodgers taking the reins in the league for the first time — as too was former Anfield coach Steve Clarke, who was appointed Baggies' manager in the summer.
As the two new managers took their respective seats in the Hawthorns dugouts for the first time in charge in the league, an atmosphere bristling with excitement greeted kick off.
Liam Ridgewell had the game's first opportunity, skewing over from the edge of the area after bundling his way into space on the edge of the area with two minutes played.
Next, Long dispossessed Lucas Leiva on the left-hand side of the visitors' box, but couldn't get an effort from a tight angle on target.
Liverpool's first chance came on 10 minutes, with Luis Suarez shimmying his way past both Jonas Olsson and Gareth McAuley before seeing his powerful 20-yard blast parried to safety by Ben Foster.
The Uruguayan was at it again moments later, twisting and turning his way into space inside the box and having a low drive blocked by the 'keeper.
It was proving an absorbing contest at the Hawthorns, with both teams looking dangerous in attack, but Suarez was left to rue a missed opportunity to open the scoring on the half-hour mark. The unmarked No. 7 was picked out inside the six-yard box by Johnson's cross, but contrived to head over the crossbar when a goal appeared inevitable.
The chances continued to come, and when Suarez's driven cross was only half cleared to the edge of the box by McAuley, Johnson raced onto the loose ball but could only blast a volley high into the stands.
West Brom hearts were in mouths again soon after when Gerrard's deflected free kick fell for Lucas in a dangerous area inside the box, but the Brazilian couldn't get the ball under control quickly enough to fashion a strike at goal.
But with two minutes of the half left, the hosts took the lead. A West Brom corner was nodded to the edge of the box by Skrtel, Gera pounced and let fly with a volley that left Reina with no chance of stopping and gave Albion the advantage heading into the interval.
Liverpool began the second period positively and Suarez spun a free kick around a West Brom wall but narrowly wide of the post as the visitors set about attempting to muster an equaliser.
But their hopes of taking something back to Merseyside were dashed in a crazy five-minute spell which saw them reduced to 10 men and concede two penalties, one of which extended the Baggies' lead.
First, with 57 minutes on the clock, Agger was adjudged to have knocked Long off balance as the striker raced down on Reina's goal, and the defender promptly received a red card from referee Phil Dowd.
West Brom's No. 9 took the resulting penalty himself, but was denied by a smart stop from Reina.
However, just moments later, the hosts were celebrating the award of a second spot kick after Skrtel was deemed to have tripped Long.
Odemwingie took responsibility this time, and made no mistake as he fired home from 12 yards.
Liverpool were stunned, but Suarez could have reduced the deficit instantly had his close-range effort been a few inches lower.
At the other end, James Morrison was left holding his head in his hands as he spurned a glorious opportunity at close quarters.
However, West Brom did manage a third when substitute Lukaku was on hand to head in Long's cross to ensure the home side would claim victory.
Photo via Twitter/Gerrard Indonesia