Top scorer Harry Kane was back on the bench from an ankle injury absence to see deputy Vincent Janssen add to his catalogue of painful misses before Dele Alli magnificently opened the scoring with his 16th league goal of the season.
England colleague Eric Dier and Son Heung-min joined in the fun with similarly emphatic strikes from outside the box, although Watford boss Walter Mazzarri will lament poor closing down on the first and third Spurs goals.
Watford appeared simply helpless as they were cut open for Son to add a sumptuous fourth, their ambitions of stringing together three consecutive top-flight wins for the first time this season having long since evaporated.
It amounted to a far more assured route to victory for Mauricio Pochettino’s side than the remarkably frantic midweek comeback at Swansea City and cut Chelsea’s advantage at the summit to four points, at least until Antonio Conte’s men face Bournemouth in Saturday’s late kick-off.
Janssen almost had his first Premier League goal from open play when he cleverly spun Craig Cathcart in the ninth minute, forcing Heurelho Gomes to save with his legs.
It was an assured start from Walter Mazzarri’s side, but they should have fallen behind in the 19th minute when Janssen’s combination of dwindling confidence and wretched luck came to their aid.
Kieran Trippier stunned a volley across the face of goal and, although the Netherlands international was partially unsighted by Watford defender Adrian Mariappa, Janssen inexplicably managed to hit the crossbar after the ball spun up off his thigh two yards from goal.
Shortly afterwards, the outstretched and beleaguered striker failed to get the decisive touch on another dangerous Trippier cross, while he strayed needlessly offside following a fine run and pass from Alli.
The England midfield stunningly took matters into his own hands in the 33rd minute, exchanging passes with Son before arching a dipping effort over Gomes and into the top corner.
Son was involved once more in the 39th minute when his deflected cross fell kindly for Dier to venomously rifle home from the edge of the area, and the South Korea winger got in on the act to effectively end the contest before half-time.
Christian Eriksen seized upon a poor headed clearance from Cathcart to feed Son, who was allowed to advance towards the area and unleash a crisp left-footed shot from 25 yards into the bottom corner, moving into double figures in the Premier League this term.
Tottenham’s dominance made for a carnival atmosphere in this sun-drenched corner of north London that Son’s second ramped up even further.
Eriksen slipped a pass to the overlapping Trippier, whose delivery was again impeccable for the on-rushing Son to convert a crisp half-volley.
Janssen’s anomalous run within Pochettino’s swashbuckling squad will continue, as Kane returned to a hero’s welcome in the 61st minute.
He rounded Gomes on the end of Trippier’s lofted pass but Kane’s shot lacked power and he was agonisingly close to heading in 13 minutes from time.
Kane turned provider as Son missed out on the matchball – slotting wide when it appeared easier to score and the former Bayer Leverkusen man also had time to clip the bar.
It did not take away from a brilliant all-round Spurs display, with Kane clattering the bar from a free-kick in stoppage time as he sought a show-stopping finale to their sixth straight league win.
Key Opta Facts:
– Tottenham have won 11 Premier League home games in a row, their best winning streak at White Hart Lane since October 1987 (14).
– Watford have enjoyed just one win in their last 11 away league games (D2 L8).
– Dele Alli has been directly involved in 14 goals in 13 Premier League games for Tottenham in 2017 (10 goals, 4 assists).
– Alli (40) has had a hand in as many Premier League goals before turning 21 as Frank Lampard (15), Steven Gerrard (13) & David Beckham (12) combined.
– Son Heung-Min has had a hand in five goals in his last three Premier League games (4 goals, 1 assist), after none in the five before that.
– Via his 10 and 11th league goals this season, Son is the first South Korean player to hit double figures in a single Premier League season.
Source Yahoo Sports