Watford 0 Tottenham Hotspur 1: Last Sunday a brave performance against the league leaders ended in traumatic defeat. Last night a farcically bad performance against Championship opposition ended in victory: a strange end to a strange week for Tottenham Hotspur.

Spurs might be the third-best team in England but at Vicarage Road they were comprehensively out-played by the 38th. Watford dominated the first half, harassing Spurs into errors, and creating a good set of chances before Rafael van der Vaart scored with Tottenham's first proper shot. Not dispirited, the home side pressed and pressed in the second half, and hit the woodwork twice, but somehow could not force a replay.

"How we won that game I'll never know," said a baffled but relieved Harry Redknapp, who made it to the ground for kick-off after another day at Southwark Crown Court. "It's better to be lucky than good sometimes, and we were lucky today. Amazing: we just never played. We passed and gave it away, they pressed us and won it back. We just never got going."

Watford, in 18th place having lost three Championship games in a row, played confident and authoritative football from the start. "If they played like that every week they'd be top of the league," Redknapp added. "You need a future in your performance," said the Watford manager, Sean Dyche, "and that has a future."

Dyche's hard-working team pinned back Spurs, provoking uncharacteristic errors in possession from Younes Kaboul, Luka Modric and Scott Parker in the opening spell. Marvin Sordell forced Carlo Cudicini into a near-post save after six minutes. Joe Garner and Prince Buaben, supporting Sordell from midfield, threatened before Sordell could not quite convert Troy Deeney's near-post cross.

Tottenham's system was not helping. With Gareth Bale absent, and Aaron Lennon and Benoît Assou-Ekotto on the bench, Spurs were shorn of the wing-play that makes them so dangerous. All of their starting front six were instinctively central players; in those rare moments when they did have the ball there were few options.

But in something as English as the FA Cup, class obviously matters. Three minutes before the break a Watford attack broke down, Kyle Walker surged forward and found Van der Vaart in space. The Netherlands international turned and, from 25 yards out, struck the ball into the bottom corner. "We've only had one shot," crowed the Spurs fans.

Addressing the imbalance of his team at the break, Redknapp replaced Modric with Lennon, although without the hoped-for impact. "I thought maybe the system wasn't working," he explained, "so I changed it [from 4-3-1-2] and went to a [midfield] four, how we always play, and that was even worse, so I thought: 'that's good, it's not my fault.' We tried everything, really."

The pattern of the first half continued. Watford pressed quickly and soon created a double-chance. An incisive passing move ended with Sean Murray curling a shot onto the far post, before Deeney, from a good position, skewed the rebound wide.

Even with the comfort of a lead, Tottenham could not take control of the game. The Spurs defence was powerless after 67 minutes when John Eustace, described as "outstanding" by Redknapp, met Murray's corner but headed it against the post. Another corner, from the lively substitute Mark Yeates, was headed wide by Murray himself.

Watford continued their assault: a long free-kick presented a chance to Nyron Nosworthy, which was saved, and one to Sordell, which was blocked. Yeates was the next to threaten, but this time the shoulder of Michael Dawson intervened.

An extra body in midfield was required, with Lennon suffering with another hamstring pull, and Steven Pienaar came on for Defoe, who, like most of his team-mates, struggled to impose himself on the game. "At the end it was hanging-on time, just hanging on," said Redknapp.

In the final minutes it was only Kaboul who saved his colleagues from the distraction of a replay, blocking and tackling like a man who already has plans for a week on Wednesday that do not include playing Watford at White Hart Lane. Thanks to some remarkable good fortune, they will not have to.

Match Facts

Watford: Loach, Hodson, Nosworthy, Mariappa, Doyley, Deeney, Buaben, Garner, Eustace, Murray, Sordell

Spurs: Cudicini, Rose, Kaboul, Dawson, Walker, Van Der Vaart, Livermore, Parker, Modric, Adebayor, Defoe

Substitutes: Watford Yeates (Murray, 67), Whichelow (Garner, 80). Tottenham Lennon (Modric, h-t), Pienaar (Defoe, 80), Pavlyuchenko (Adebayor, 90).

Booked: Watford Hodson Man of the match Sordell

Match rating 6/10

Possession: Watford 45% Tottenham 55%

Attempts on target: Watford 12 Tottenham 4

Referee C Foy (Lancashire)

Attendance 15,384