In a game that Welfare really had to take maximum points from they finally delivered the goods and moved off the bottom of the Premier Division in the process.
Michael Carmody’s men got off to the perfect start when Craig Morley nodded home a free-kick with just two minutes on the clock.
Armthorpe continued to press for the second goal which finally arrived in the 65th minute and was no more than they deserved.
Another free-kick was delivered into the area and there was Mansaram to emphatically head past the helpless goalkeeper.
It was almost 3-0 ten minutes later as full back Jack Waldron saw his shot cleared off the line.
However, Armthorpe did grab a third to wrap up the points when Mansaram scored his second of the game from a tight angle with ten minutes remaining.
Barton pulled one back in added on time through when Jonathan O’Callaghan curled in a free-kick from distance.
Armthorpe make the short trip to mid-table Worksop Town on Saturday.
After thrashing neighbours Denaby United 6-0 in the Sheffield Senior Cup first round earlier in the week, Maltby Main went into their home clash against Rainworth Miners Welfare looking for a first league win in five - but they had to settle for a 2-2 draw as the visitors came from two goals down to rescue a point.
Steve Hopewell and Shawn Mitchell were on target for the Miners.
Rossington Main slumped to a third Division One defeat on the spin as they lost 3-1 at Teversal.
Just when it looked like Main would get to the break on level terms, the home side grabbed the lead on 41 minutes through a Craig Mitchell effort.
It got worse for Rossington when Teversal doubled their lead inside the first minute of the second half, James McCann curling in a shot from the tightest of angles.
It was all over bar the shouting just past the hour when Tom Laister tucked home the third from close range.
Rossington kept going and grabbed a deserved consolation effort from Jason Stokes in injury time.
Rossington will hope to return wining ways when they host Grimsby Borough this weekend.
After their struggles of last season, which saw Grimsby finish third bottom in Division One, they are proving to be something of a surprise package this term as they arrive at Oxford Street fifth in the table and with just one defeat in their last eight league outings.