Sunderland clinched the Championship title after beating play-off chasing West Ham courtesy of Stephen Elliott's late winner at Upton Park.
Sunderland players celebrate being champions
The Hammers took a deserved lead just before half time when Marlon Harewood lashed in a left-foot shot.
But Julio Arca scrambled in from close range for Sunderland before West Ham thought they deserved a penalty for an apparent handball by Stephen Caldwell.
And Elliott compounded the home side's misery by driving in an angled shot.
West Ham's defeat meant Preston are definitely in the play-offs - as they now cannot finish outside the top six.
Sunderland manager Mick McCarthy:
"I keep hearing we are not the best side in the Championship.
"But I think that when people read the papers in the morning, they will find that we are.
"To go up as champions is just reward for what we have achieved this season. Put it this way: I think the players will have a pretty good weekend."
West Ham manager Alan Pardew:
"It's not over. The players put in maximum effort against Sunderland, and if we do that at Watford then we can win.
"Nerves are always going to play a part. We have a young team, especially in the centre of the field, and we were playing the best team in the league.
"We sat back a bit too much after half time, and Sunderland were able to play in the space between our defence and midfield."
West Ham: Walker, Powell, Ferdinand, Ward, Repka,
Etherington (Noble 73), Reo-Coker, Mullins, Newton (Rebrov 81),
Subs Not Used: Bywater, Fletcher, Chadwick.
Booked: Repka, Harewood, Noble.
Goals: Harewood 43.
Sunderland: Alnwick, McCartney, Breen (Danny Collins 74),
Caldwell, Wright, Lawrence, Whitehead, Robinson, Arca,
Brown (Deane 89), Stewart (Elliott 75).
Subs Not Used: Welsh, Carson.
Goals: Arca 52, Elliott 87.
Ref: R Beeby (Northamptonshire).