Two key moments went against us - Roberto Soldado failed to take advantage of a golden opportunity when he broke clear with the tie still all-square on 30 minutes and in the second half, Federico Fazio's pass was intercepted and Fiorentina broke away to score the opening goal through Mario Gomez.
The Serie A side then secured their place in the last 16 when Mohamed Salah fired home the second on 71 minutes.
Mauricio Pochettino shuffled his pack as we entered the first of two huge games for the Club this week. In defence, only Jan Vertonghen remained from the draw with West Ham as Vlad Chiriches came in for only his fourth appearance of 2015, with Fazio partnering the Belgian in the heart of the back four. Ben Davies returned at left-back as Danny Rose and Kyle Walker took up places on the bench, while Eric Dier was rested.
Benji Stambouli partnered Nabil Bentaleb in front of the back four with Nacer Chadli, Christian Eriksen and Erik Lamela in front of them and Soldado in attack.
Level at 1-1 from the first leg, the teams entered to a cauldron of noise with a packed house and over 2,000 Spurs fans as we sold our full allocation of tickets for the trip to Tuscany.
With an away goal safely tucked away in Fiorentina’s back pocket, the onus was on us to attack the home side who defended deep and narrow, looking to catch us on the counter.
Fiorentina’s shape meant there was space to be found on the wings and that was the case when Soldado galloped down the right on nine minutes and squared for Eriksen to tee up Lamela, who tested Neto with an awkward volley.
After a quiet spell the game burst into life with 15 minutes gone when Chadli found room in behind Micah Richards before his cross was cleared, allowing the home side to counter. Gomez had already been penalised for being offside on numerous occasions but sprung our offside trap on this occasion and looked to be clean through on goal before he miscontrolled, allowing Vertonghen to get back and see off the danger.
We started to take the upper hand as we edged the home side back towards their own goal and won a series of set-plays that caused problems in the Viola penalty area, though Neto remained a spectator for much of it.
The opening we had been waiting for duly arrived just before the half-hour mark when Lamela broke and played in Soldado who had beaten the offside trap along with Chadli. The pair were completely free with just Neto to beat but Soldado undercooked a square ball for his team-mate, allowing the goalkeeper to smother the danger.
It was a let-off for Vincenzo Montella’s side who been second best for the majority of the half though still posed a threat through the pace of Salah, and the on-loan Chelsea forward would have been disappointed not to do better when he sliced an effort wide at the end of the first half as the sides went in locked at 0-0.
There was a more even feel to the start of the second half and the home side should have grabbed the lead after 50 minutes when Davies’ clearance fell kindly for Milan Badelj but the Fiorentina midfielder scuffed his effort straight at Hugo Lloris.
Less than five minutes later though and the home side grabbed the lead in the tie. A mistake by Fazio allowed Gomez to be played through and the forward made no mistake as he slotted the ball firmly past our skipper.
In some ways the goal didn’t change the standing in the overall tie. We needed a goal at the start of the night and with 35 minutes to play that was still the scenario to stay in the competition.
Things almost got worse though, but for a great one-on-one save from Lloris to deny Salah, before Andros Townsend and Harry Kane were introduced with just under 30 minutes to play as Chadli and Bentaleb made way.
As time ticked away, again the home side dropped deeper to defend, looking content with their slender advantage but with 20 minutes left they doubled their lead through Salah. Gomez turned a ball into his path which looked like it would be cleared by Vertonghen but Salah picked his pocket and prodded past Lloris to all but end our hopes of reaching the last 16.
We thought we had found a way back into it with 15 minutes to go when Davies found space on the left and squared for Kane to tap home but the referee’s assistant had already flagged for offside against the Welshman.
Chances were few and far between from there and the closest we came to pulling a goal back was when Soldado glanced Townsend's free-kick just over.
Roll on Wembley on Sunday!
Fiorentina: Neto, Richards, Badelj, Pizarro (C), Fernandez (Aquilani, 25), Savic, Joaquin (Pasqual, 84), Basanta (Rodriguez, 57), Alonso, Gomez, Salah. Substitutes (not used): Lezzerini, Babacar, Tomovic, Ilicic.
Spurs: Lloris (C); Chiriches, Fazio, Vertonghen (Walker, 75), Davies; Bentaleb (Kane, 63), Stambouli; Chadli (Townsend, 63), Eriksen, Lamela; Soldado. Substitutes (not used): Vorm, Rose, Mason, Paulinho.
Goals: Fiorentina - Gomez (54), Salah (70).
Yellow cards: Fiorentina - Badelj (36), Salah (71). Spurs - Davies (50).
Referee: Husseyin Gocek.