Cape Town - The start to the second leg was almost a carbon-copy of the first in Italy a week ago, with Tottenham started strongly. The hosts almost went ahead in controversial circumstances, though, after Dele Alli nearly tapped in from close range.
In the build-up, the ball clearly passed the whitewash for a Fiorentina throw-in but the assistant referee failed to see it despite being no more than a yard away.
Josip Illcic and Christian Eriksen then traded efforts from distance for their respective sides as the 20-minute mark approached; the latter hit with much more precision and stinging the palms of Ciprian Tatarusanu in the Fiorentina goal.
Illic then proved to be much more of a threat just minutes later when cutting inside from the right flank and curling narrowly beyond the far post in a cut-throat breakaway by the visitors.
The deadlock was broken in the 25th minute, with Alli at the heart of another Tottenham move. He ran straight across the Fiorentina defensive line to help the ball into Mason's path, who then had the composure to neatly tuck home from inside the area and into the bottom-right corner.
Fiorentina had just one opportunity before the break to level the tie back up on aggregate, but midfielder Borja Valero could only head into the side netting when rising to meet a free-kick whipped in from the left flank.
Both sides wasted little time in showing their attacking intent at the start of the second half. Nacer Chadli was caught marginally offside as he zoomed through the Fiorentina defence, while the visitors' retort was a side-footed strike from Valero which forced a save from the returning Hugo Lloris.
There was a hint of offside when Tottenham launched their next attack at goal and Lamela looked to break beyond the defence. The flag stayed down, though, and the Argentine was on hand to fire in the rebound to create a serious uphill battle for the Viola.
Fiorentina threw on Mauro Zarate to try and claw the Serie A side back into the tie, but their captain Rodríguez piled on further misery by turning Tripper's cross into his own net.