Sitting just a point clear of the relegation zone coming into the contest, Luton made a dream start with a breakthrough inside three minutes.
Ross Barkley picked the ball up inside the box after a marauding run from Andros Townsend, and the influential midfielder threaded a pass into the path of Tahith Chong, who rifled a clinical finish into the bottom corner.
Stunned by that early setback, the hosts looked to find an immediate response, but Timo Werner dragged a golden opportunity wide of the far post.
Tottenham continued to probe for an equaliser, and Son came within inches of levelling the scores when his angled effort struck both posts before Pape Matar Sarr’s follow-up strike was cleared off the line.
Grateful for that close escape, the visitors settled into a more resolute defensive shape with HT approaching, limiting Spurs to little in terms of clear-cut chances in the final third.
The hosts came flying out the blocks in the early stages of the second period, and their pressure was duly rewarded within six minutes of the restart, as Brennan Johnson’s delivery was inadvertently turned into his own net by Issa Kaboré.
Armed with the momentum, Spurs went in pursuit of a quickfire second, but Thomas Kaminski stood firm in the Luton goal to thwart Son from close range.
The match remained tantalisingly poised heading into the final quarter-hour, and Johnson thought he’d given the hosts a late lead when his shot appeared to cross the line.
However, goal-line technology came to Luton’s rescue to keep the visitors on level terms.
Not to be denied, Spurs finally found the game’s all-important third goal with four minutes remaining, as Son kept his composure to tuck home from Johnson’s clever cut-back.
The result lifts the hosts above Aston Villa into fourth on goal difference, while Luton’s winless run extends to 10 matches (D3, L7).
Flashscore Man of the Match: Brennan Johnson (Tottenham Hotspur)
