Huddersfield secured a second season in the Premier League after clinging on for a draw with Chelsea at Stamford Bridge.
David Wagner's side needed a point to secure their top-flight status following a draw at champions Manchester City on Sunday and they repeated that feat to deal a huge blow to Chelsea's hopes of nicking a Champions League spot.
Laurent Depoitre gave Huddersfield a shock lead early in the second half and Town held firm after Marcos Alonso's fortuitous equaliser to claim the draw they required.
The result left Swansea needing to overturn a three-point and nine-goal difference to Southampton on the final day to stay up or else face joining West Brom and Stoke in the drop.
Chelsea had come into the game on a four-match Premier League winning-run as they put in a late-season charge towards the top four.
But this result means that Liverpool now only need a draw against already-safe Brighton and Hove Albion on Sunday to assure themselves of a top four finish and Champions League football next season regardless of what last year's Premier League champions do at Newcastle.
The Terriers drew at Manchester City on Sunday and claimed another point against City's predecessors as champions after Laurent Depoitre stunned the hosts with an opportunist strike.
Although Mathias Jorgensen's attempted clearance ricocheted in off Marcos Alonso's face for a Chelsea equaliser, Huddersfield held on to survive ahead of Sunday's game with Arsenal.
Chelsea will complain about time-wasting and gamesmanship from Huddersfield, but they had chances.
Antonio Rudiger should have scored twice and Jonas Lossl saved brilliantly to deny Andreas Christensen following a late goalmouth scramble.
Speculation is rife that Antonio Conte will leave Chelsea this summer, despite guiding them to the title last season. This was not how the Italian would have chosen to bow out if this is his last home match at Stamford Bridge.
Chelsea had to do something City could not and find a way through Huddersfield. Patience was required of the Blues, perseverance from the visitors.
Conte made six changes following Sunday's win over Liverpool, with goalkeeper Thibaut Courtois missing due to a back injury.
Like Conte, Courtois has 12 months remaining on his current contract and, with Chelsea unlikely to gamble on him leaving for nothing, the Belgian may have played his final game at Stamford Bridge unless he agrees an extension.
Willy Caballero was little more than a spectator in goal as the visitors sat deep with a flat back five, outnumbering restored striker Alvaro Morata.
Alonso had a shot parried by Lossl and next Rudiger missed a glorious chance from two yards out after Cesar Azpilicueta had headed a corner to the far post.
As Cesc Fabregas and Conte pointed out pre-match, too often this season Chelsea have failed to score, not just the strikers.
Shortly after half-time Willian was tackled in midfield by Huddersfield Chris Lowe, with a hint of a foul which was not given. It was not the first time Chelsea were frustrated with referee Lee Mason.
The ball broke for Aaron Mooy, who floated the ball over for Depoitre to chase.
The burly Belgian beat Caballero to the ball and stayed on his feet as the goalkeeper tumbled in the contact.
Depoitre got the luck of the bounce and showed composure to prod the ball by the recovering Rudiger to spark celebrations from the visitors. It was Depoitre's first goal since December 23.
Conte called for reinforcements. On went Giroud for Davide Zappacosta and then Eden Hazard for Pedro.
The equaliser owed more to good fortune than the super subs. Azpilicueta's cross was met by Jorgensen, whose attempted clearance hit Alonso's face and went in.