Watsonians climbed to fourth position on Tuesday night following their 5-0 victory over bottom club Grove Menzieshill at Peffermill.
Coultas himself commanded midfield all night and goals by Fraser Sands, Danny Cain, Robbie Greenhaugh, Roderick Craig and Andrew Fraser-Harris secured the points against a Dundee side who offered little up-front but stuck to their task.
Coultas said: “It was a solid performance built on our successful defence. We could have had a few more goals but we targeted a top-six finish before the break and we have achieved that."
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The men’s Premiership table has Watsonians on 17 points from nine games and they are in fourth spot on goal difference from Dunfermline Carnegie, the early pace-setters.
Grange have 23 points, two adrift of leaders Western Wildcats, who have a game in hand. That means success for them over Watsonians is a must if they want to stay in the title race.
At the other end of the table, Grove are bottom with one point from eight games and a goal difference of minus 40, having only scored five goals and conceded 45.
They must pick themselves up to face city rivals Dundee Wanderers at Dawson Park on Saturday (3.40pm).