Laursen rose above Jamie O'Hara to fizz in a header from Gareth Barry's excellent delivery as the game looked to be heading for a draw.
Villa have now hit the top six once again and claimed two successive victories.
The home side dominated the game from the outset with Luke Moore, who started in place of the injured John Carew, coming closest early on. He turned neatly inside the Spurs box but sliced just wide of Paul Robinson's goal.
Hero Laursen was next to miss a good opportunity and he looked more of a zero as he hit the ball over what was virtually an empty net.
But on 41 minutes Villa finally took the lead after Spurs gave away a free kick on the left.
Ashley Young whipped in a trademark centre and Olof Mellberg evaded Michael Dawson to claim an easy headed goal.
In truth, it was no more than O'Neill's men deserved as they had completely bossed the first half with Spurs lacking any bubbles.
The away side only had one attempt of note in the whole half and it nearly produced a goal as on form Dimitar Berbatov shot directly at Scott Carson.
Juande Ramos undoubtedly raged at his players during the break as the away side came out with renewed vigour.
Tom Huddlestone replaced the ineffectual Kevin Boateng which added a much needed passing verve to the Totenham midfield.
Huddlestone's arrival increased the confidence within the Ramos ranks and the away side dominated possession. However, they failed to create clear opportunities and so it was time for Robbie Keane's introduction.
Keane, the man so often a bain of Villa, added yet more sparkle to Spurs and eventually they claimed a leveller.
Villa target Jermain Defoe showed just what he can do as he acrobatically volleyed in after a game of pinball emerged inside the Villa box.
Defoe's strike had come after moments earlier Luke Moore again missed a golden opportunity as he slid the ball wide when it looked easier to score.
This difference in finishing class could be the reason Villa are looking for reinforcements up front and Moore could be the man to make way if Defoe does join.
However, a goalscoring touch is not lacking in the Claret and Blue defence and Martin Laursen showed the strikers how to do it as he powered home the winner.
The Villa back four have now claimed three of Villa's last four goals showing just why the Claret and Blue faithful may want to see more attacking options brought in during the transfer window.
But the main signing of the window could be from within as all fans will want to see Laursen sign on the dotted line and commit his future to the club.
So come on O'Neill sign him up!