Fletcher fired home the rebound after Rovers keeper Thorsten Stuckmann parried Reds captain Conor Hourihane’s shot into his path in the 81st minute - to settle the contest and help the Oakwell outfit clinch their fifth straight league win on home soil.
The Keighley-born forward’s first league goal for the Reds extended Rovers’ winless streak to seven matches in all competitions in the process, with Darren Ferguson’s side now worryingly just three points above the League One relegation zone.
Caretaker head coach Heckingbottom said: “We definitely deserved it. I felt we should have been in front at half-time, but speaking to the lads at half-time, we felt we had not shown the quality that we have got in the final third.
“We had great opportunities, some of which didn’t even get result in shots. We got in good positions, without quite making the most of them. We wanted to be more clinical.
“In the second half, we were still a little bit wasteful and had to wait until the last ten or fifteen minutes to get our winner.”
“But it was all about positive and going for it. We were in the ascendancy and felt we had to push for the winning goal and luckily, we got it.”
On match-winner Fletcher, he added: “He has done terrific. We are working really hard with Fletch, with little bits after training as well.
“He is doing his little extra bits, so that the next time he gets his start and opportunity, he can have the same impact from minute one.”
Heckingbottom said that the club are awaiting an assessment regarding Aidy White’s ankle injury, with the defender taken to hospital after being stretchered off after 25 minutes following a challenge from Conor Grant.
Meanwhile, Rovers chief Ferguson admitted the side’s slump in results represents a real worry, although he felt his side’s efforts deserved something on the day.
But in the final analysis, the Scot was left to rue a poor concession late on as Rovers’ alarming run continued.
Ferguson said: “In the second half, I thought we got control of the game and possession without threatening too much. Probably our best two chances in the game fell to Mitchell Lund.
“But we lost a really, really poor goal. That is what happens in games when you are on a little bit of a bad run. Maybe a month ago, we maybe would have nicked that 1-0.
“The shot was going wide for the goal and could have been left. But there we go.”
On Rovers’ slide down the table, he added: “It was a disappointing result.
“We are on a bad run, no question about that and we need to get out of it.”