Peter Odemwingie scored a hat-trick as rampant West Brom humiliated Black Country rivals Wolves to increase the pressure on manager Mick McCarthy.
The Baggies led through Odemwingie's deflected strike but Steven Fletcher equalised in first-half stoppage time.
Jonas Olsson, Odemwingie, twice, and Keith Andrews scored in 25 second-half minutes to complete the rout.
A sixth loss in seven home games saw Wolves slip into the Premier League relegation zone on goal difference.
No-one could argue with the margin of a victory in an absorbing Black Country derby.
But the manner of Wolves' defeat - against a West Brom side that are now eight points clear of the bottom three - was astonishing.
The hosts managed to weather a first-half onslaught and started the second period on level terms, but were ripped apart after the interval by Odemwingie and company and left the pitch to a chorus of boos at the end.
Only superb goalkeeping from Wayne Hennessey had kept them in the game in the first half.
He made a brilliant block inside 90 seconds to deny Jerome Thomas when the ball broke kindly off defender Sebastien Bassong after great work by Odemwingie.
The Wales international pulled off a superb reaction save to keep out Paul Scharner's deflected strike, and then stood firm to beat away Odemwingie's fierce half-volley.
Thomas - like Odemwingie, finding plenty of space on the flank - shot just wide, but Odemwingie finally broke Wolves' stubborn resistance after 34 minutes with a deflected effort from the edge of the box.
Wolves, whose claims for a penalty were refused after Gareth McAuley clumsily challenged Sylvan Ebanks-Blake, found themselves level at the break when Fletcher combined brilliantly with Ebanks-Blake and shot first time past Ben Foster.
Wolves enjoyed their only decent, prolonged spell of the match after the interval.
Fletcher almost got on the end of a right-wing Kevin Doyle cross and Fletcher saw a beautifully struck 20-yard effort hit Olsson and go just wide.
But the otherwise excellent Hennessey made a terrible hash of Olsson's half-volley following a goalmouth melee in the 64th minute.
Although Roger Johnson was unlucky not to restore parity for a second time when his fine header was cleared by Youssouf Mulumbu via the underside of the bar, West Brom started to regain their first-half dominance.
Odemwingie had a shot cleared off the line by Kevin Foley before scoring his second of the afternoon. He was first to react in the box following great work by debutant Liam Ridgewell and Olsson.
Former Wolves midfielder Andrews extended West Brom's advantage with a deflected 18-yard shot, and Nigerian Odemwingie sealed a perfect day for the travelling fans when he slotted past Hennessey after a sweeping counter-attack.