Sam Surridge pulled one back to make it 2-1 but once Albion were ahead, the outcome was never in doubt.

Unchanged Swansea threatened when Kristoffer Peterson's header deflected over the bar off Nathan Ferguson, then Sam Johnstone had to tip over Surridge's angled volley and George Byers' resulting corner.

It was not long before West Brom began to exert some control on the game however and Jake Livermore's rising 30-yard drive was tipped over by goalkeeper Freddie Woodman in the 20th minute.

Kyle Bartley was desperately close to giving the Baggies the lead when his header from point-blank range fell straight at Woodman, who smothered at the second attempt.

Bartley was involved again as West Brom took the lead in the 25th minute.

The former Swansea centre-back headed Pereira's inswinging corner back into the danger area for fellow defender Ajayi to nod home.

West Brom threatened again when Grady Diangana skipped past a challenge and lifted a shot over the bar.

It was 2-0 in the 34th minute. Pereira's first-time left-footed shot from 12 yards beat Woodman at his near post after Diangana sent Kieran Gibbs racing away on the overlap and he cut the ball back from the left. It was the Brazilian's fifth goal of the season.

Swansea pulled one back five minutes later. Peterson's inswinging corner was left by Johnstone and the grounded Surridge stabbed home at the second attempt at the far post after Bartley had blocked his first effort for his sixth goal of the campaign.

West Brom restored their two-goal cushion a minute before the break after exploiting some sloppy defending.

Livermore won the ball following a Swansea throw-in and fed Pereira, who threaded Robson-Kanu through to race clear before calmly drawing Woodman and sidefooting into bottom corner of the net.

Swansea had a let-off just before the hour when Pereira's cross was diverted goalwards by Kyle Naughton, forcing Woodman to parry.

Pereira was the architect again as Phillips made it 4-1 in the 70th minute.

The on-loan Sporting Lisbon playmaker robbed Matt Grimes easily and crossed to Phillips, who beat Woodman with a sensational diving header.

Four minutes later Edwards grabbed Albion's fifth goal. The substitute cut inside Connor Roberts before smashing the ball home after Pereira touched on Livermore's cross.