Defending PartyPoker.com Grand Slam of Darts champion Phil Taylor faces a winner-takes-all battle with Vincent van der Voort on Monday night after a 5-4 loss to Andy Jenkins.
Jenkins produced a superb performance to record the first win over Taylor in his career and ensure his spot in the last 16 of the Grand Slam of Darts.
He led 2-0 and 3-2 before Taylor hit back to lead, but the Portsmouth man sent the game into a decider before hitting a sensational 12-darter against the throw to take victory.
"I know what I have to do and I've no choice but to win or go home," said Taylor. "It's as simple as that and it's knockout darts for me now against Vincent - but that will bring out the best in me."
Jenkins is now assured of a place in the last 16, and said: "I'm so proud to have beaten Phil. He's the best player ever and it means a lot to me."
Both Raymond van Barneveld and James Wade, ranked second and third in the Professional Darts Corporation, came from 3-1 down to win 5-3 with superb displays against Robert Thornton and Denis Ovens.
Wade's 111.03 average was his highest in a televised event, while included a 121 finish in maintaining his unbeaten start to the tournament.
Mervyn ensured his place in the last 16 with a 5-3 defeat of Colin McGarry, while PDC World Champion John Part will progress following a 5-1 defeat of Kevin McDine.
Darryl Fitton's 5-2 win over Paul Nicholson puts him in the driving seat in Group H, while ITV Wildcard Qualifier Wes Newton took a second successive victory with a 5-3 defeat of Darin Young.
Monday's play sees Groups A-D play their final games, with three players in Group B still able to qualify.
Unbeaten Andy Hamilton meets Simon Whitlock, while Alan Tabern takes on eliminated player Brian Woods.
Group C sees unbeaten King face BDO World Champion Mark Webster and Colin McGarry take on winless Michael van Gerwen.
John Part, who has qualified in Group D, takes on Wayne Mardle, while Kevin McDine - who has far superior leg difference to Mardle - meets Women's World Champion Anastasia Dobromyslova, who could still qualify with a 5-0 victory.