AEL looked set to inflict a shock defeat on Mauricio Pochettino's side until the Argentinian's game-changing introduction in hot and humid conditions.
It is fair to say neither club nor player will have been pleased with the way things have gone since the 22-year-old arrived last summer in a club-record £30million deal.
Lamela managed just three league starts for Spurs in an injury-disrupted debut season but at last he is showing signs of promise, with his introduction here the catalyst to Tottenham's victory.
It had looked for a long time like Spurs would flounder at the Antonis Papadopoulos Stadium in Larnaca, where a bobbly, cut-up pitch was compounded by temperatures in the 30s and a spirited display from their opponents.
Pochettino, making his managerial debut on the continental stage, was also frustrated by his own players, with the returning Jan Vertonghen and Paulinho making mistakes in the build-up to Adrian Sardinero's 14th-minute opener.
Off the pace and out of sorts, it did not look like Spurs would have enough to force an equaliser - yet the introduction of Lamela gave them a creative edge they were lacking.
Just minutes after his introduction, the Argentinian sent a wonderful clipped ball which Roberto Soldado exquisitely struck home and, with 10 minutes remaining, he impressively played through Harry Kane to secure Tottenham victory.