Sunderland 1-2 West Brom
West Brom will join Sunderland in Nationwide Division One next season despite beating the Wearsiders at the Stadium of Light.
Derek McInnes scored both goals for the Baggies, but Bolton's win over West Ham ended West Brom's slim hopes of avoiding the drop.
Marcus Stewart gave the home side hope on 70 minutes, but it was not enough to prevent Sunderland's 11th successive defeat.
The home side had dominated the opening 15 minutes and the result could have been a lot different were it not for the heroics of Russel Hoult.
The Baggies keeper pulled off two stunning saves within seconds in the eighth
minute to deny Stewart and Kevin Kyle.
But West Brom soon found their stride and both Jason Koumas and Danny Dichio came close to opening the scoring.
39 mins: McInnes puts West Brom in front
42 mins: McInnes grabs his second goal of the season
70 mins: Stewart hits back for Sunderland
And the visitors' pressure paid off six minutes before half-time.
Neil Clement's cross seemed to pose no real threat, but a collision between Sunderland keeper Mart Poom and defender Talal El Karkouri allowed McInnes to steer the ball into the empty net.
Worse was to follow for the Estonian keeper three minutes later when he was wrong-footed by Koumas' free-kick, and although he saved with his legs, McInnes slid in to make it 2-0.
West Brom were brimming with confidence and Poom partially redeemed himself with a good save from former Sunderland striker Dichio on 62 minutes.
Sunderland reduced the deficit when Hoult failed to hold Sean Thornton's well-struck drive, allowing Stewart to bundle the ball home from close range.
Mick McCarthy's men stepped up a gear in the search for an equaliser and Stewart should have done better on 82 minutes but the striker blazed his shot across the face of the goal.
It needed a fine reaction save from Hoult to keep his side in front two minutes later when Phillips got a flick to McCartney's goal-bound header.
The home side continued to press until the final whistle, but the Baggies held on for a deserved, if hollow victory.
Sunderland: Poom, Gray, Craddock, El Karkouri (McCartney 58),
Williams, Kilbane, McCann (Arca 19), Thornton,
Kyle (Proctor 82), Stewart, Phillips.
Subs Not Used: Sorensen, Flo.
Booked: El Karkouri, McCartney, Williams, Kyle.
West Brom: Hoult, Balis, Sigurdsson, Wallwork, Gregan, Clement,
Koumas, McInnes, Johnson, Dichio, Hughes (Roberts 36).
Subs Not Used: Murphy, Dobie, Lyttle, Udeze.
Referee: G Poll (Hertfordshire).