Briggs, who came through the West Brom youth system before going on to have a career in non-league - has guided the USL Championship side all the way to the cup final.
And they were set to become the first side from a lower division to lift the trophy since 1999.
In the semi-final they made their way past Sporting Kansas City on penalties after a 0-0 draw.
They went into their clash with Orlando as major underdogs - and so it proved as the MLS side ran out 3-0 winners.
The Wolverhampton born Briggs' side held out until the 75th minute when Facundo Torres fired home - before his 80th minute spot kick all but killed the game.
And the result was completed in the sixth minute of stoppage time as Benji Michel fired home to give City the win.
It completed a remarkable journey for Briggs and his players, with the former Baggie telling his squad after the game: "Be proud of how you have represented this club, be proud of how you have represented this city.
"Everyone in this stadium knows that is not the right results. Get your heads up, stay strong. I am so proud of you."