With both Liverpool and Manchester City winning, the loss leaves Spurs nine points adrift of the top of the table with only 10 games of the season now left to play.
A goal from Pedro early in the second half gave Chelsea the lead, while Kieran Trippier's own goal in the closing stages sealed Tottenham's fate at Stamford Bridge.
Spurs failed to get anything going at the other end, in what was the first Premier League game of Pochettino's reign in which the team was unable to muster a single shot on target.
"We made mistakes and lost the game, that is why we are disappointed," the Argentine coach told BBC Match of the Day after the final whistle.
For the first time under Mauricio Pochettino, Tottenham have failed to register a shot on target in a Premier League match ❌#BTSportScore pic.twitter.com/5YGQkKuDCD
— BT Sport Score (@btsportscore) February 27, 2019
"Chelsea had one shot on target and one goal and we didn't shoot - it's difficult that way to win and we weren't solid enough. In the small details the result was decided for Chelsea," he added.
"The competition will put us in our place. It's a 10-month competition, not just three or four months. After Burnley I said it was difficult, and tonight makes it impossible to fight Man City and Liverpool. Only they can win the league - we must fight to win games and to be fair."
The next challenge for Spurs is picking themselves up in time for the visit of Arsenal in a highly anticipated north London derby in Saturday's early kickoff. With the title race already out of reach, a third straight defeat could be disastrous as it would move the Gunners just one point behind and suck Pochettino's team into the fight just to finish in the top four.
Source : 90min