Saturday's results at the bottom of the league had left Charlton needing to win their final two matches of the season to escape the drop, but they never remotely looked like achieving the victory that would have kept their hopes alive and at times the gulf in class between the two sides was embarrassing.
Charlton got off to the worst possible start by conceding that early goal as Berbatov, showing skill and strength, left defender Talal El Karkouri in his wake as he raced for goal and finished in style.
Charlton had a couple of first-half chances as Alex Song headed wide from Darren Bent's cross and then Bent himself fired wide.
While Spurs played with poise, Charlton could only hit hopeful long balls up to the isolated Darren Bent and their only real chance of the second half could have come from a possible penalty when China international Zhi Zheng appeared to be brought down by Michael Dawson, but referee Mark Halsey gave a corner.
Charlton's last throw of the dice was to send on strikers Jimmy Floyd Hasselbaink and Lloyd Sam, but Spurs produced the killer punch when substitute Defoe hit a fine individual goal.
Despite seeing their team fall into the Championship, the Charlton supporters sang 'Always look on the bright side of life', but they may have to face next season with the departure of a number of key players as Alan Pardew - the club's third manager this season who took on an almost impossible survival job when he arrived on Boxing Day - will seek to rebuild his side.
With two matches still to play - against Blackburn Rovers and Manchester City - Spurs should confidently achieve a UEFA Cup spot if they show the kind of form and commitment that won them this match in such comfortable style.