Chelsea’s lead at the top of the English Premier League now stands at only four points and the title race is wide open again after they were well beaten on Sunday.
The leaders were beaten 2-0 by a resurgent Manchester United at Old Trafford.
United manager Jose Mourinho has suffered this season against the club where he was a three-time champion, losing 0-4 in the league at Chelsea.
He also lost out of the FA Cup quarter-final at Stamford Bridge.
The Portuguese was not to be denied this time as Marcus Rashford, paired with Jesse Lingard up front while a jaded Zlatan Ibrahimovic was rested, finished coolly after seven minutes.
Ander Herrera — detailed to do a brilliant man-marking job on Eden Hazard — saw his shot deflected in off Kurt Zouma four minutes after the break.
Zouma was a late replacement for Marcos Alonso, who pulled out in the warm-up, but Chelsea can offer no excuses here as they were second best throughout.
Tottenham now trail them by four points with six games to go and have the superior goal difference.
Chelsea looked to be strolling to the title just a few weeks ago — but a sudden stumble, including the home defeat by struggling Crystal Palace, has held them back.
And an irresistible surge from Spurs have brought renewed edge to the run-in.
Conte will feel his side did not enjoy the best of luck here, with goalkeeper Thibaut Courtois ruled out with a training injury, while Alonso was withdrawn after the warm-up.
Referee Bobby Madley also missed what appeared to be a clear handball from Herrera as he intercepted Nemanja Matic’s pass before sending Rashford clear for the opener.
The Blues are still in a strong position but they are now feeling the hot breath of Spurs on their neck.
This was after Pochettino’s team made it seven successive league wins for the first time since 1967 with a 4-0 home win over Bournemouth on Saturday,
So, Spurs have the momentum, but Chelsea still have a four-point lead, which counts for a lot with only six games left.
The Blues’ run-in also looks a little kinder, with home games against Southampton, Middlesbrough, Watford and Sunderland — but a real test to come at Everton.
The pressure, however, is now applied and there may be twists left in this race and Spurs will feel renewed hope.