Valerien Ismael's side made it difficult for the foxes but ultimately fell short by the one goal.
Patson Daka opened the scoring in just 11 minutes, after Dennis Praet was fouled inside the box. The Zambian forward was clinical from the penalty spot once again, for his seventh goal of the campaign.
This would prove costly as Ricardo Pereira doubled Leicester's lead, 10 minutes into the second half, a blistering attack cutting through the heart of the Watford midfield, a goal exemplifying the Maresca style.
Despite late pressure where Mads Hermansen was forced into a couple of saves, City held out for another victory maintaining their lead at the top, leaving Ismael's side with positives to take.
Watford lacked quality
On a day where the table toppers were not at their best, Watford would rue the missed opportunity to not take at least a point away from proceedings.
Ismael Kone found himself in some threatening positions, breaking through the lines, a lack of attacking runs from deep resulted in Watford being fairly passive.
With just one goal in the last three league games, it is an area for concern. However, the returning talisman of Dennis will bolster the attacking options, especially after scoring.
Patson Daka scores again
At the start of the season, Daka was nowhere near the starting lineup. Making his first league start in December, since then the Zambian has excelled in-front of goal.
Accumulating three goals in his last two appearances away from home, and now an expert from the penalty spot. Confidently slotting the ball low past former fox Ben Hamer, putting Leicester ahead early on.
A striker who is more suited to running behind defenses he has had to adapt his play style significantly. Facing away from goal and linking the play with the advanced eights. Both Wesley Hoedt, and Ryan Porteous did not know whether to press or not.
When the system is executed correctly, it is a nightmare for defenders, it is no surprise they are the Championship top scorers.
Positives for Watford
Despite a poor run of form continued today with another defeat, The Hornets sit just four points away from the play offs, if a performance of that calibre can be replicated against teams below them, their form is bound to turn around.
Both sides just had three shots on target apiece, although that does not always reflect the full game, the home side made a good account of themselves. Leicester knew they were in a game and were forced into bringing in defensive reinforcements late on to see out the victory.
With a number of missed opportunities late on, some fans will be left with a feeling of 'what if'.
Foxes game management
On course to break a Championship record, there has been little negativity around City this season. In the odd games where points have been dropped, the decisive goal has often came late on. Such as, the dropped points against Coventry City and Ipswich Town last month.
The away side dug deep late on and dealt with the home pressure very professionally. Despite a few chances in the last 15 minutes, the only attempt on goal in additional time came via Stephy Mavididi.
Giving Enzo Maresca a birthday to remember, securing a staggering 24th league win of the season in February.
Despite conceding, a rather new backline was in operation with 19-year-old Ben Nelson making is full league debut in place of the injured Jannik Vestergaard, it looked fairly secure.
With back-to-back home games next up for Leicester, their next away test is a trip to Elland Road, where game management could be more pertinent that ever.