The Seagulls have managed to swoop for the £4.5m midfielder and are close to completing the signing.
Caicedo, 19, has been tracked by a host of Premier League clubs, including West Ham and Everton too.
In late December, United appeared to be the frontrunners to land him from Independiente del Valle.
And according to the Daily Mail , Chelsea were in fact his preferred destination.
But Frank Lampard’s side only got as far as making enquiries for the talented teenager following their £200m spree in the summer market.
Despite reports of United being close to getting Caicedo, it is suggested no offer was ever actually made by Ole Gunnar Solskjaer’s team.
With a switch to Stamford Bridge and Old Trafford not guaranteed, Brighton have pounced.
Graham Potter’s side pushed to reach an agreement while their rivals hovered.
And Brighton now hope to have the deal finalised in the coming days.
Caicedo is due to undergo a medical before arriving at the Amex Stadium for the second half of the Premier League campaign.
The youngster has already been capped four times by Ecuador at senior international level, showing he has a bright future ahead of him.
Chelsea and United, meanwhile, will hope their failure to clinch Caicedo’s signature does not come back to haunt them.
Lampard is keen on strengthening his midfield but his priority is West Ham star Declan Rice, although his £80m price-tag makes any deal unlikely right now, especially with the Chelsea manager in trouble at present.
United have managed to add to their squad this month already, with young winger Amad Diallo finally arriving from Atalanta in a deal which could end up being worth up to £37m.