"This has been the most crazy and beautiful experience of my life," said the pug lover, whose mentor, Mel B, was unable to attend the final due to illness.
More than 80,000 people auditioned, 16 made it to the live finals and three remained to fight to be crowned the 2014 winner on Saturday's finale weekend.
The night kicked off with a group performance of Rule the World with Take That with Faustini admitting that he was "honoured" to be performing with such legends.
First up to take to the mic was Ben Haenow, who has enjoyed an incredible week touring with his Battle Bus around London, singing to fans and drumming up support from the public. The former van driver then sang an emotional version of Imagine Dragons' Demons.
"You are what this competition is about," said Tulisa Contostavlos as Cheryl Fernandez-Versini said that his fantastic song choice said that it was a "professional" performance and wished him all the best of luck for the final.
"You’ve remained a down to earth, normal guy, a family guy…genuinely this is why this show was created- to find and give people like you a chance," praised Simon Cowell.
Next to perform was Andrea Faustini who met with friends and family this week in London but was sad that his father couldn't visit England for the final due to illness.
The pug lover sang was fortunate enough to sing at the Royal Albert Hall and wowed the judges with his performance of Nina Simone's I'm Feeling Good.
"You took that to church and back brother!" said Cheryl before Simon said that despite Mel B not being there, he did an incredible rendition of the song and had done "brilliant". “Your voice is amazing,” praised Tulisa Contostavlos.
Finally, the last female of the competition, Fleur East, was seen taking to the city, performing in her town hall with her friends and dance crew before the finale.
She then took to the stage performing Can't Hold Us, originally sang by Macklemore & Ryan Lewis.
"You deserve the final a million per cent," said Louis Walsh, while Tulisa said that she was a star who "owned the stage".
"For ten years it hadn't worked but for the last two weeks I've seen you transform into someone really really special…if you're not in the final then something has gone terribly wrong," said Simon.
All About That Bass star, Meghan Trainor then wowed the audience with her hit number one single before Ben sang a heart melting duet of Thinking About with Ed Sheeran.
Next to perform together was Andrea and former X Factor contestant Ella Henderson who sang Ghost before Fleur East sang Beneath Your Beautiful with Labrinth, after he requested to perform with her to Simon.
Spicing up the night, the entertainers of the programme performed a medley of including acts ranging from Katie Waisel, Wagner, Chico, Chloe Jasmine to Stevi Ritchie.
After another incredible performance by Ed Sheeran, the results were in and Dermot O'Leary announced that Fleur East would be the first act through to the final on Sunday, shortly followed by Ben Haenow.
Tune in on Sunday at 8pm for the final of X Factor 2014 to see whether Fleur or Ben will be crowned the winner.