The late dismissal of Federico Fazio and subsequent penalty converted by substitute Jeronimo Barrales made it a nervy ending, but we ultimately made it back-to-back victories against the Greek side in Group C.
Mauricio Pochettino made nine changes to the team that started against Villa on Sunday. Jan Vertonghen, who captained the side and Christian Eriksen were the only survivors from Villa Park and they were joined by Michel Vorm, Eric Dier, Federico Fazio, Ben Davies, Mousa Dembele, Benji Stambouli, Andros Townsend, Erik Lamela and Harry Kane.
It was Vorm's first European appearance for us while young goalkeeper Luke McGee, 19, was on the bench for the first time in a competitive match having made his debut in the friendly against Chicago in July.
Ben Davies proved our attacking outlet as we controlled the early stages but a number of forays down the left came to nothing.
At the other end, Giorgos Zisopoulos headed wide from Facundo Parra's corner as Asteras looked to sit in and catch us on the counter-attack.
Lamela was first to fire on target with a crisp 25-yarder straight at Tomas Kosicky on 22 minutes and Asteras went close five minutes later when Khalifa Sankare rose highest to meet Martin Rolle's teasing, inswinging free-kick but his header was wide of the target.
Pablo Mazza had the best chance of the opening half-hour as Asteras started to come more into the game but dragged his shot wide from 16 yards.
We opened the scoring on 36 minutes. Townsend darted into the box on the left, Sankare committed himself to a flying challenge and mistimed it, taking the winger down with him.
Townsend picked himself up, grabbed the ball and smashed it past Kosicky from the spot - his second goal in the Europa League and second penalty after scoring in the play-off, second leg against AEL Limassol.
We soon doubled the lead and Townsend was central to it again. This time he put on the burners down the left to leave Braian Lluy in his wake before clipping a delightful cross to the far post where Kane rose to power home his header.
Roberto Soldado replaced Lamela at half-time and Asteras carved out their best two chances so far within 90 seconds of the restart.
The best fell to Tasos Tsokanis who burst through on goal in the right channel, placed his shot wide of Vorm but a yard the wrong side of the post. Rolle then fired just wide from 20 yards.
We responded with a 25-yarder from Eriksen that Kosicky claimed well down to his right and Townsend's low drive that zipped two yards wide.
It was end-to-end now and Parra had two chances within a minute. The first saw him get away from Vertonghen and Fazio before shooting just wide and for the second, he chopped back onto his right foot but blasted over from 16 yards.
Ryan Mason entered the fray for Eriksen on 63 minutes and Asteras came even closer to scoring two minutes later as Mazza, on the left side, hit a dipper that beat Vorm but cannoned back off the inside of the post.
Soldado had the next chance of note on 74 minutes. Intitially picking the ball up on halfway, he exchanged passes with Kane before volleying just wide from 25 yards.
Giorgos Zisopoulos went close twice in the 84th minute as Asteras continued to threaten, his first effort coming back off Dier with Vorm clawing away his second attempt from eight yards out.
Gianniotas' low drive was steered goalwards by substitute Ziguy Badibanga with a clever flick with the inside of his boot as he turned on the edge of the box but it was stopped low on his line by Vorm, before Asteras finally did get a goal back in the 90th minute.
Fazio brought down Jeronimo Barrales in the box and, as the last man, was shown a straight red card. Up stepped Barrales to fire the penalty down the middle to reduce the arrears.
And it didn't stop there. Two minutes into stoppage time, Badibanga headed powerfully in the direction of the goal but thankfully for us it flew into the side netting.
We saw out the remainder of stoppage time to remain unbeaten in the group, although it was much closer than the previous match against Asetras at the Lane a fortnight ago.
Asteras Tripolis: Kosicky; Lluy, Sankare, Zisopoulos, Panteliadis; Munafo (Gianniotas, 81), Usero, Rolle; Mazza, Parra (Barrales, 84), Tsokanis (Badibanga, 60). Substitutes (not used): Theodorooulos (GK), Fernandez, Bakasetas, Kiriakopoulos.
Spurs: Vorm; Dier, Fazio, Vertonghen (C), Davies; Dembele, Stambouli; Townsend, Eriksen (Mason, 63), Lamela (Soldado, 46); Kane (Paulinho, 77). Substitutes (not used): McGee, Chiriches, Rose, Chadli.
Goals: Spurs - Townsend (36, penalty), Kane (42). Asteras - Barrales (90, penalty).
Yellow cards: Asteras Tripolis - Sankare. Spurs - Mason.
Red cards: Spurs - Fazio.
Referee: Javier Estrada (Spain).