Warrington gatecrashed the party of their arch rivals with a 39-12 victory at Langtree Park to keep St Helens waiting for their first trophy for six years.
Saints needed only a point to ensure they would finish top of the First Utility Super League for the first time since 2008 but the League Leaders' Shield was put back in its case after the Wolves ran in seven tries, two of them from the league's leading scorer Joel Monaghan, to ruin their big night.
St Helens will still get their hands on the shield if Castleford lose at home to Wakefield on Sunday, otherwise they will have another chance to clinch it with a win at coach Nathan Brown's former club Huddersfield in their final league game next Friday.
Warrington's emphatic victory, which was sweet revenge for their opening-day 38-8 home defeat back in February and lifts them up to second place, came despite a spate of injuries, most seriously to loose forward Simon Grix, who was carried off on a stretcher with a suspected broken ankle just 17 minutes into the match.
The Wolves also lost co-captains Michael Monaghan and Ben Westwood before half-time, although the former was able to return in the second half, while St Helens lost full-back Shannon McDonnell with a facial injury at half-time.
Saints were a shadow of the team that won at Leeds last Friday yet they made a dream start when skipper Paul Wellens passed out of the tackle and forward Anthony Laffranchi's inside ball got McDonnell over for his third try in as many games for the club with just three minutes on the clock.
Tom Makinson's goal made it 6-0 but the Wolves struck back four minutes later when Stefan Ratchford, restored to the side at right centre, dummied his way over for their first try.
The visitors then established a vice-like grip on the game with the aid of three penalties and three goal-line drop-outs, largely the result of the fine kicking game of half-backs Richie Myler and Gareth O'Brien.
The visitors shrugged off the loss of Grix to go in front when Michael Monaghan dummied his way over from acting half-back before providing the spark for a long-range try for brother Joel.
The hooker put second rower Trent Waterhouse through a gap deep inside his own half and Myler took play on before sending Monaghan the winger over for a glorious score.
When O'Brien dummied his way over on 24 minutes for his side's third try in seven minutes and Ratchford kicked his third goal, there seemed no way back for Saints.
But when Michael Monaghan was withdrawn on 26 minutes after taking a heavy knock and Westwood limped off four minutes later, the game took a twist.
Saints received their first penalty after half an hour, to ironic cheers from the crowd, and immediately grabbed their second try, with substitute Willie Manu taking Wellens' clever pass and wrong-footing full-back Matty Russell.
Makinson's second goal cut the deficit to 22-12 but Saints could not cut out the errors and paid the price.
Myler added a drop goal on the stroke of half-time and Warrington increased their lead further six minutes into the second half when Myler took Micky Higham's pass to dummy his way over for their fifth try.
Saints' miserable night was summed up on 52 minutes when prop Mose Masoe fumbled the ball 30 metres from his own line and Warrington centre Ryan Atkins kicked ahead on the resulting free play for Joel Monaghan to grab his second try, his 26th of the campaign.
Ratchford took his goal tally to four and Atkins added a seventh try on 63 minutes after swooping on a wayward Saints pass inside their own half.