A wonder goal from Riyad Mahrez saw Leicester took another step closer to completing the unthinkable and winning the Premier League.
After Tottenham and Arsenal played out a thrilling 2-2 draw at White Hart Lane earlier on Saturday, Claudio Ranieri's side knew a victory at Watford would move them five points clear with nine games remaining.
And the fearless Foxes made no mistake with Mahrez, a £400,000 signing from French second division side Le Havre, scoring the only goal of the game with a spectacular strike after 56 minutes.
Leicester, who were able to recall N'Golo Kante, started the game with the confidence of a team flying high at the top of the table.
After just two minutes Jamie Vardy was already causing problems for the home side's makeshift defence with Nathan Ake operating as an emergency centre back after Miguel Britos sustained an injury in the warm-up.
A long ball over the top from Marc Albrighton found Vardy who rounded Heurelho Gomes only for Ake, the on-loan Chelsea defender, to stand in his way. Moments later, left-back Christian Fuchs drew a fine save from Gomes after Odion Ighalo failed to clear a Leicester corner.
It was a relentless opening from the Foxes, and midway through the opening period, Vardy, operating on the shoulder of Ake, was through on goal once more, but his left-footed half-volley was well wide.
Vardy then combined with Mahrez only to put his effort wide when it appeared easier to score. Manager Ranieiri, who has become accustomed to Vardy finding the back of the net this season, threw his arms up in celebration only to see the Englishman's effort ricocheted off the side netting.
Leicester were looking the more likely to score, but as the half grew on Watford, gained a foothold in the match. Yet the promoted side, who have now failed to score in seven of their last nine league outings, were struggling to create any chances of note.
After fine work from Nordin Amrabat and then Ighalo, their best effort of the first half fell to Troy Deeney, but a sliding block from Danny Simpson took the sting off the Watford captain's shot with Kasper Schmeichel gobbling up the ball.
A scrappy start to the second half ensued, but Mahrez provided the spark with a goal befitting of the Premier League leaders. Jose Holebas, an eleventh-hour replacement for Britos, failed to clear his lines and when the ball fell to Mahrez on the edge of the penalty area there only ever seemed like there was going to be one outcome.
The Algerian shifted the ball on to his left foot and shaped it past the diving Gomes who had no chance in the Watford goal. It was Mahrez's 15th Premier League strike of an incredible campaign and he led the celebrations with the away fans who now know their dream of winning the league is quickly becoming a reality.
Leicester were buoyant with Gomes quickly denying them a second after a fine header from Robert Huth while Vardy was continuing to cause the hosts problems with his speed on the counter-attack.
Watford pressed for an equaliser, but it always appeared unlikely
"We're going to win the league", the Leicester fans sung and with Newcastle and Crystal Palace to follow, it was hard to disagree.