Swansea 3 West Brom 1 match report
Albion crashed to defeat as sublime Swansea's first-half master-class ended the Baggies' winning run.
Two goals in two minutes from Michu and Wayne Routledge put Swansea in total control before Routledge added a third before the break.
Romelu Lukaku pulled a goal back in first-half stoppage time but despite an improved second-half Albion's four-match winning run is over.
Lukaku was recalled for Shane Long while Youssouf Mulumbu returned for Zoltan Gera – who was missing for the squad completely.
Luke Moore made the Swansea bench against his former club as Danny Graham continued to miss out through illness.
And Albion survived a scare after just two minutes when Michu latched onto Pablo Hernandez's chip to wriggle free of Billy Jones and strike the post from an angle.
It was a bright start from the hosts and they opened the scoring on nine minutes when Hernandez knocked back Nathan Dyer's deep cross and Michu stole in ahead of Jonas Olsson to ram in.
It got worse two minutes later when Routledge doubled the hosts lead after awful Albion defending.
Hernandez was allowed to swap passes with Ben Davies and burst into the area and Olsson's attempted clearance from his cross cannoned in off Routledge.
Albion were rocked with Lukaku isolated up front as the Swans easily sliced their way through the visitors' midfield.
Jones and Liam Ridgewell were enduring torrid nights as the Baggies struggled to deal with Swansea's intensity.
They finally had their first shot after 29 minutes when Peter Odemwingie fired wide from 25-yards and it looked like they had begun to stem the Swansea tide.
They survived a penalty shout when Chris Brunt barged over Dyer before Gareth McAuley blocked Hernandez's effort on 35 minutes.
But Routledge added his second and Swansea's third on 39 minutes when he drilled in Davies' low cross after Odemwingie and Jones were again exposed.
Lukaku then gave Albion hope in the third minute of first half stoppage time when he rifled in Brunt's corner after Ki inadvertently flicked it on.
It was a glimmer of hope for the Baggies and Lukaku had a chance to make it 3-2 two minutes after the restart but slashed McAuley's bouncing ball over.
Albion had switched to 4-4-2 at the break, with Odemwingie partnering Lukaku, and were much improved without seriously hurting the hosts.
Swansea were content to kept Albion at arm's length as they played within themselves but Michu almost added a fourth on 70 minutes when he headed Hernandez's cross wide.
KI Sung-Yueng hit the side netting from a free kick after Leon Britton's awful dive conned Lee Mason.
Michu then tested Boaz Myhill but the game had been won in the first half as Albion failed to recover.