Warbury can only hope to finish as runners-up after letting a two-goal lead slip against a St Louis United side who have surpassed all expectations in their debut season in the World League.
The Americans took the lead through Tommy Gunn in the 12th minute before Jack Duffy equalised ten minutes before half time.
Second half goals from Callum Angelo and Lee Prendergast looked to have given the Warriors all three points until an own goal from Darren Head and a second strike from Gunn two minutes from time gave St Louis the point they deserved.
Whatever happens in the final game next week, it's a hugely disappointing season for Warbury, who were again the favourites to win the title. There will surely be a major clear-out of their older players next season - and even the future of manager Kurt Panzer must be in doubt.
This season's unlikely champions are Lima Incas, who, like St Louis, are newcomers to the World League. They beat rivals Mombasa Mambas - last season's champions - 2-1 to clinch the title.