The match began in a competitive in a fiercely forced manner with both teams aware of the importance of winning and it was the home side who looked the more eager side in the early exchanges.
It was no surprise when they took the lead in the eighth minute, Philippe Brinquin's excellent cross from the right was met by the head of Juanjo Camacho and the Spanish striker scored powerfully from the edge of the six-yard box.
The ball may have taken a slight deflection off the head of Mark Wilson, but it was a good finish never the less.
This gave Livi the lift they were looking for and they stepped up a gear showing good confidence on the ball. In the 28th minute Francisco Quino forced a superb save from Paul Gallacher with a right-foot shot from just inside the box.
United had a even closer scare in the 36th minute when David Bingham latched on to a loose ball inside the area, but he saw his left-foot shot hit the base of the post and go out for a goal-kick.
The nearest Untied came close to scoring in the first half was in the 31st minute when Craig Easton's shot was blocked by Marvin Andrews and the big defender managed to clear the ball before the lurking Jim Hamilton could step in.
United came out fighting in the second half and captain Easton raced fully 50 yards with the ball but his final pass was terrible and the chance was wasted.
Things went from bad to worse for the Tangerines in the 51st minute when Andrews headed a Lee Makel header past Gallacher from six yards.
In the 66th minute, United had Gallacher to thank for keeping them in the game when he saved a shot from Rolando Zarate who was clean through six yards out.
United were inches from scoring in the 83rd minute, when Jim McIntyre curled the ball past Javier Sanchez Broto only to see it come back off the post. That miss proved costly when Bingham played a one-two with Camacho and chipped the ball over Gallacher from six yards.
United go bottom of the table after there third successive 3-0 defeat, while this victory eases some of the pressure on the home side.