"We'll see. If they fail, our job is done because we are there, but still it's up to them to win the Premier League".
A ideal day for Spurs took another positive turn when Mauricio Pochettino gave the fit-again Kane 30 minutes of action at the end of the match, and the striker had the chance to mark his return with a goal 10 minutes after his introduction when he latched on to a pass from Trippier and rounded the keeper, only to see his tame finish cleared by the defence.
Crystal Palace breathed new life into a title race that appeared to be foregone conclusion before their unexpected win at Stamford Bridge last weekend.
'Pau Lopez is very young but he's here because we believe in and trust in him, ' the Argentinian added.
'Now it's up to them to win the league'. By then, the score was already 4-0 mainly thanks to Son.
Their fifth consecutive victory maintained the seven-point gap and means Pochettino's side have amassed 29 points since the turn of the year - more than any other side.
It means that 22-year-old Lopez, a Spain under-21 global on loan from Espanyol, could feature against Watford as Spurs bid to be crowned champions of England for the first time since 1961.
Tottenham were at their tantalising best as the side ran riot against Walter Mazzarri's visitors.
- Dele Alli has been directly involved in 14 goals in 13 Premier League games for Tottenham in 2017 (10 goals, 4 assists).More news: Westbrook becomes 2nd player in NBA history to average a triple double
Kieran Trippier stunned a volley across the face of goal and, although the Netherlands global 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.
Can the resurgent Watford FC side storm into White Hart Lane and grab a third straight victory to secure their place in the middle of the Premier League table?
As the first half wore on, too, Abdoulaye Doucoure and Tom Cleverley in the Watford midfield lost the control they had in the early minutes, dropping deeper toward their own goal.
From an easy miss to an excellent strike - Alli gave Spurs the lead on the 33rd minute with a curling effort from 25 yards out.
Son crashed in his second on the volley in the 54th minute after which the hosts cruised through to full-time.
The striker had only himself to blame for his failure to claim a hat-trick, placing a shot wide from Kane's lay-off and later hitting the bar from Trippier's cute pass.
The Spurs have been one of the hottest teams in the Premier League over the last three months, winners of 12 in their last 15 matches, with just two losses.
Troy Deeney has scored against 41 different teams during his Watford career, but has never scored in four appearances against Spurs for the Hornets.