Albion suffered only their second Premier League defeat at the Amex since last April against Crystal Palace.
Ismaila Sarr scored the only goal after 61 minutes as Palace ended their long winless run to move above Albion in the table.
Babis Kostoulas forced a fine save from Dean Henderson just after the only goal and by the end Albion had five attacking players on the pitch but they couldnât break down a resolute Palace defence.
Harry Howell goes past Tyrick Mitchell during an accomplished first Premier League start. đˇPaul Hazlewood.
Fabian Hurzeler made Harry Howell Albionâs youngest Premier League starter and the 17-year-oldâs composed debut on the right was a big positive for Albion.
The Amex atmosphere had been at its boisterous best at kick-off and Albion, kicking towards the north stand in the first half, won a couple of early corners to increase the decibel level even further.
As expected when these sides meet players had little time on the ball and tackles were flying in with Will Hughes booked for a lunge on Georginio Rutter.
Pascal Gross waits for developments as Yeremy Pino tries to clear. đˇJames Boardman
Neither goalkeeper was tested in the first half. Lewis Dunkâs reaction after he met Pascal Grossâs free-kick only to head wide from eight yards suggested he knew it was a good opportunity on an afternoon when there were few of them.
Maxim De Cuyperâs goalbound volley cannoned to safety off Maxence Lacroixâs left knee and Albion carried the greater threat until the closing stages of an untidy 45 when Jorgen Strand Larsen and Ismaila Sarr had opportunities for Palace but neither could test Bart Verbruggen.
There was little change to the pattern of the game at the start of the second half before the key moment of the contest. Palace sub Evann Guessand he ran at a retreating defence before spotting the unmarked Sarr to his left. The pass was perfect and Sarr had time to take a touch before lashing a left-foot shot past Verbruggen.
Georginio contests a header with Maxence Lacroix. đˇPaul Hazlewood.
Albion would have levelled almost immediately but Dean Henderson kept out Kostoulasâs right-foot shot after the Greek striker broke clear of the Palace defence.
Albion continued to push in the closing stages but there was no way through.
Albion: Verbruggen, Kadioglu, Dunk, Boscagli, De Cuyper (Welbeck 70), Baleba (Gomez 70), Gross, Howell (Minteh 70), Mitoma, Rutter (OâRiley 82), Kostoulas (Hinshelwood 82).
Subs not used: Steele, Igor, Milner, Veltman.
Referee: Thomas Bramall
Attendance: 31,179