Hull's 2-2 draw against Cardiff in an equally dramatic clash at the KC Stadium meant victory for the Hornets would have been enough to secure top-flight football next season, but the Whites spoiled the party at Vicarage Road
Dominic Poleon opened the scoring for the visitors in a clash delayed for a lengthy period due to a serious injury to Watford goalkeeper Jonathan Bond, before the Hornets levelled through Almen Abdi's superb curling effort.
As the hosts piled forward looking for the goal needed to clinch promotion, Leeds broke at the other end and replacement `keeper Jack Bonham let Ross McCormack's lob squirm through his hands and roll into the beck of the net to condemn Watford to defeat and a play-off semi-final against Leicester.
"It was an amazing game," McDermott said. "Obviously we knew what was going on at Hull but we did what we had to do. I had a feeling Ross McCormack would make a difference.
"Gianfranco (Zola, Watford boss) is a friend of mine and I feel for him but during the game you have to do what you have to do.
"He's a top person who has done a fantastic job, and they still have every chance of going up."
Hull's draw left them needing Leeds to do them a favour in the closing stages, and Tigers boss and ex-Manchester United defender Steve Bruce needed to find an unlikely ally in the Yorkshire club.
"I don't think I've ever been supporting Leeds but wow, for Leeds United to do it for me is remarkable," Bruce said.
- Sports & Recreation
- Dominic Poleon