The visitors scored four times themselves, but were left shell-shocked after leading 3-2 and 4-3 midway through the second half in a goal fest in north London.
Dave Kitson, a boyhood Tottenham fan, returned to the place where he fell in love with football to score twice, but even his heroics weren't enough for Steve Coppell's men.
Steed Malbranque and Jermain Defoe were also on the scoresheet for the home side, while Ivar Ingimarsson and Kalifa Cisse both notched for Reading.
It took just six minutes for Spurs to take the lead when Malbranque's incisive through ball released Keane and the Republic of Ireland striker crossed for Berbatov to smash past Marcus Hahnemann at the far post.
Reading could scarcely thread two passes together with Coppell's men looking unrecognisable from the team that clinched a deserved 1-1 draw at West Ham on Boxing Day.
But they were gifted an opportunity to equalise after Paul Robinson's inability to gather Nicky Shorey's left-wing free-kick enabled Cisse to fire home through a ruck of players.
That goal appeared to give Reading a new sense of belief and Stephen Hunt saw his drive deflected inches past the post as the visitors stepped up a gear.
Shorey went close again for the visitors with a curling free-kick from 20 yards after Aaron Lennon chopped down Bobby Convey on the edge of the penalty area, while Keane flashed an effort wide as Spurs looked to rouse from their slumbers.
Tottenham tried to up the pressure before the break after a dire first-half showing and they should have gone into the break a goal ahead, but Keane failed to convert from close-range.
The striker had the goal at his mercy after Berbatov had picked out his team-mate just two-yards from goal, but Keane failed to connect as the ball ran away to safety.
It was Keane that threatened once again in the opening few minutes of the second half as he took Pascal Chimbonda's header in his stride before pirouetting towards goal only to stumble at the vital second.
Chimbonda was in the thick of the action once again as his expertly timed challenge deniedKitson the chance to shoot at goal, but from the following corner, Reading found themselves back in front.
Shorey's left-footed delivery caused panic in the home defence and Ingimarsson escaped the attentions of Tom Huddlestone to head into the ground and past Robinson.
Reading almost doubled their lead just seconds later as Kitson burst into the Tottenham penalty area, but Robinson blocked at the striker's feet as the visitors threatened to run riot.
Robinson had to be alert once again as Reading became rampant and Hunt's flashing effort was brilliantly tipped away, before a comedy of errors saw Kitson drag his effort inches wide of the post.
With Tottenham rocking, Reading seemed destined to score but they were hit by a sucker punch as Juande Ramos' side somehow found themselves level.
Defoe, who had only been on the pitch a matter of seconds, crossed into the penalty area and Graeme Murty's failure to score allowed Berbatov to smash high into the roof of the net.
It was a goal that Tottenham had scarcely deserved, but with their tails up, the hosts continued to pile forward in search of another.
But it was Reading that struck next as Kitson headed home Shorey's corner after escaping the attentions of Younes Kaboul inside the box.
That lead only lasted three minutes, however, as Berbatov smashed home his hat-trick after Jermaine Jenas' corner had found its way to the Bulgaria international inside the box, only for Kitson to restore Reading's lead two minutes later.
Hunt ran the length of the pitch before playing in Kitson and the flame-haired striker dinked the ball over Robinson with panache.
The drama failed to stop there though and Malbranque curled home Huddlestone's pass to make it 4-4 as goals continued to rain down on White Hart Lane.
Defoe then smashed home a rebound after Keane's penalty had been saved by Hahnemann, while Berbatov slotted home a sixth after latching onto a long ball from Kaboul.