Saido Berahino scored the winner on his return to the starting line-up as a really well-organised West Brom side secured a deserved 1-0 victory at the home of local rivals Aston Villa.
Albion have yet to concede a goal on their Premier League travels this season and they produced another masterful away performance here, keeping a subdued Villa side very quiet.
And Berahino, who threatened not to play for the Baggies again after the club rejected transfer bids for the England U21 forward from Tottenham, marked his first start since then by touching a James Morrison shot into the net just before half-time to win it for the visitors.
The Baggies are up to 10th in the table but problems are mounting for Villa, who barely had a shot in anger and are just a point and a place above the drop zone.
West Brom made the brighter start and almost led inside three minutes when Chris Brunt sent over a lovely cross from the left and Salomon Rondon nodded it goalwards, only for Brad Guzan to pull off a good reflex save.
Jonny Evans then headed over the crossbar from a Villa corner but the hosts gradually began to improve and Claudio Yacob blocked a Carles Gil effort, after Gabriel Agbonlahor had done well down the left.
But Guzan remained the busier keeper and he had to plunge to his left to keep out a curling effort from Darren Fletcher which was heading for the bottom corner.
And the visitors grabbed the lead five minutes before the break after Craig Dawson was too strong for Jordan Amavi down the right-hand side. The ball broke to James McClean and his cross found its way to Rondon, who teed up Morrison for a shot which Berahino did well to divert past Guzan.
Villa brought big striker Rudy Gestede off the bench at half-time but Rondon was making more of an impact at the other end and Guzan nervously grabbed the ball at the second attempt after the Baggies forward had turned neatly on the edge of the box and unleashed a powerful drive.
Carlos Sanchez had fired over from distance at the other end, and the hosts were then denied a leveller in somewhat controversial fashion with 20 minutes left.
Micah Richards headed into the net after a Jack Grealish cross but referee Martin Atkinson had already blown the whistle for a foul on the Villa youngster.
To add to the misery of the home fans, Ashley Westwood put the subsequent free-kick over the bar and, although the hosts put plenty of crosses into the box in the final 15 minutes, Evans and Gareth McAuley led the way as West Brom defended competently, and in numbers.
Villa finally got a half-chance in stoppage-time when Lenadro Bacuna sent over a good cross from the right and his fellow sub Gestede rose to meet it at the near post but he sent his powerful header over the bar and the home fans began to head for the exits.
West Brom celebrated jubilantly at the final whistle, experienced manager Tony Pulis having masterminded another fine away display, while Villa boss Tim Sherwood was left to wonder how he can get more out of his below-par side.
Soccer Saturday verdict - Charlie Nicholas
"I have watched Aston Villa maybe three times this season and I have been encouraged with some of their performances in an attacking sense, Micah Richards was a good signing for them, but today I didn't see any real quality from them. West Brom bossed this from the start.
"Some of them look scared. The quality, the craft, guile was poor. He could have subbed any one of six or seven for me today. It was a very average and tame performance from them. Whereas West Brom, it was a very together, well-drilled, well-organised setup."
Player ratings:
Aston Villa: Guzan (7), Richards (6), Lescott (6), Hutton (6), Amavi (5), Westwood (5), Sanchez (5), Grealish (6), Sinclair (5), Agbonlahor (6), Gil (6).
Substitutes: Bacuna (6), Veretout (6), Gestede (6)
West Brom: Myhill (7), Evans (7), Brunt (6), McAuley (8), Dawson (7), Yacob (5), Morrison (7), McClean (6), Fletcher (7), Berahino (7), Rondon (7)
Substitutes: Olsson (6), Gardner (6), Lambert (6)
Man of the match: Gareth McAuley