Scarborough took the lead in just the fourth minute, captain Michael Coulson converting a penalty into the bottom corner after being pulled down in the box.
Brig equalised on 43 minutes with a penalty of their own, Ali Waddecar continuing the theme of being fouled in the box and scoring the penalty himself.
Remarkably, for the second home game in a row, there was then a third penalty, awarded to Scarborough.
Coulson stepped up again but this time his penalty was excellently saved by Danny Roccia in the Brig goal, before Watson’s late goal from 30 yards meant an unlucky Brig ended the game with no points.
The game started at a fast pace, Roccia quickly called into action to keep the ball out with his feet from close range.
The visitors then won a corner and Coulson was brought down whilst jumping for the ball in a packed 18 yard box.
Coulson struck his penalty hard and low into the bottom corner, sending Roccia the wrong way.
Brig then began to have sustained spells of pressure in the Scarborough half, Waddecar cutting inside before curling an effort narrowly over the bar.
Scarborough were threatening on the counter, however, and Watson scuffed a shot wide of the post from close range on 31 minutes.
The opening for Brig came on 43 minutes, Waddecar fouled by the defender whilst jumping inside the box.
Brig’s highest ever appearance maker made no mistake from the spot, that his fifth goal from his last three games.
The second half began with Joey Collins’s men continuing on the front foot and Waddecar ran through on goal only for his effort to be denied by a last-minute block from Isaac Assenso.
Dudley then flicked a header towards goal but it was safely caught by Thomas Taylor in the Scarborough net.
Dom Roma then had a chance for the visitors inside the area after holding off several Brig defenders, but he scooped the ball wide of Roccia’s post.
Brig’s pressure then continued from the other end and captain Matt Lawlor was unfortunate to see his header loop over the bar on 77 minutes.
The big decision from the referee came four minutes later, Kian Spence adjudged to have been clipped by Dudley as he advanced into the 18-yard box.
Captain Coulson stepped up again but was this time denied by a fine save from Roccia.
Both sides then had chances late on but it was the visitors who stole the three points in the second minute of stoppage time.
Roccia made a superb save to prevent a goal bound free kick from hitting the top corner, but the ball found its way to Watson who fired home from 30 yards to hand Joey Collins’s side a defeat that was harsh on them overall given the balance of play.
Match Reporter - Ryan Smart (@rssport2)
Full gallery of match photos available here: BBFC Flickr