Bale put Spurs in front with a header in the 16th minute and after Roman Pavlyuchenko had missed a penalty, he made amends by heading the second four minutes before the interval.
Peter Crouch added a third in the 68th minute before Bale scored his second of the game from a cross by Alan Hutton.
Blackburn rallied too late with goals from substitute David Dunn in the 79th minute and a Gael Givet effort in the closing stages.
The home side had dominated the early stages of the game took the lead with their first real chance.
A corner on the right from Rafael Van der Vaart in the 16th minute was firmly headed home at the near post by man of the moment Bale. The header, into the roof of the net, gave former Tottenham goalkeeper Paul Robinson little chance.
Blackburn responded in the 22nd minute with a curling shot from Brett Emerton which was tipped around the post by Tottenham keeper Heurelho Gomes.
Tottenham were denied a penalty in the 24th minute when Luka Modric was upended in the box but referee Andre Marriner booked the Spurs midfielder for diving.
In the 28th minute, Tottenham should have increased their lead but after latching on to a bad backpass by Phil Jones, Pavlyuchenko sent his shot over the bar with only Robinson to beat.
Spurs were awarded a penalty in the 31st minute when Robinson was adjudged to have brought down Crouch - but Pavlyuchenko's afternoon got worse when he sent his spot-kick wide of Robinson's right-hand post.
Blackburn made a change in the 35th minute when Michel Salgado was replaced by El-Hadji Diouf.
Gomes pulled off a smart double save in the 38th minute to deny Nikola Kalinic and then Emerton, before Pavlyuchenko - a constant threat to Rovers - he forced Robinson into another good save before making it 2-0 in the 41st minute.
A typical Bale run down the left was followed by a cross to the far post, where Pavlyuchenko rose unmarked to head home.
Blackburn replaced Kalinic with Jason Roberts at half-time but Tottenham continued to dominate the game, although their first real chance of the second half came on the hour when Bale's cross fell on to the bar.
Moments later, Robinson foiled Modric when the Spurs midfielder tried his luck from the edge of the penalty area.
But Spurs had William Gallas to thank in the 61st minute when he cleared a shot from Morten Gamst Pedersen off the line. It was the Blackburn striker's last act of the game as he was replaced seconds later to be replaced by Dunn.
Gomes saved Spurs again in the 66th minute when he produced a fine stop to deny Diouf.
But Spurs made it three in the 68th minute after Robinson had saved Pavlyuchenko's shot, Givet dithered on the ball and Crouch seized the chance to send a shot into the roof of the net.
Bale grabbed his second of the game in the 76th minute when he slipped the ball home from a cross by Alan Hutton, before Blackburn substitute Dunn fired a 79th-minute goal for Rovers with a 20-yard drive.
Spurs defender Younes Kaboul then cleared off the line when Diouf's shot had beaten Gomes in the 83rd minute, before Givet got Blackburn's second with a thunderous 18-yard shot in the 89th minute.