The striker finished from a tight angle five minutes before the end of the first half to claim his 11th goal of the season - exactly the total he hit in two seasons at Tynecastle before leaving the administration-hit club in the summer.
The last time Motherwell sealed a sixth consecutive win in Scotland's top division they inflicted Celtic's record defeat, an 8-0 win in the 1936-37 season, and they created enough chances to put this game out of sight before half-time.
But Hearts rallied against the odds in the final half hour to give Motherwell goalkeeper Gunnar Nielsen some uncomfortable moments, and they were applauded off the park by the home crowd despite falling 20 points adrift following Ross County's draw with Partick Thistle.
Hearts had Jamie Hamill back from suspension and filled their bench for only the second time in six games but there was little let-up for their stretched squad, with Callum Tapping joining Danny Wilson on the sidelines through illness.
They lifted their crowd with a couple of attacks in an end-to-end start but Jordan McGhee almost put through his own net in the third minute following Motherwell striker James McFadden's low cross, with Jamie MacDonald diving to stop the ball on the line.
McFadden soon set up another chance with a mazy run but Iain Vigurs shot weakly from 18 yards and MacDonald held.
Sutton headed over from 10 yards as Motherwell continued to attack at every opportunity, and they soon outnumbered Hearts by three to one on the break. McFadden's pass found Lionel Ainsworth but Robinson got back to make a diving block and McFadden volleyed wide from Ainsworth's follow-up cross.
The chances kept coming as Ainsworth robbed Kevin McHattie and rolled the ball across the penalty box but Vigurs mis-hit his effort.
The on-loan winger then beat two men and struck a ferocious shot just over from 25 yards and was on target five minutes later with an equally powerful volley that MacDonald dived to push away.
Motherwell's pressure told in another counter-attack. Brad McKay misjudged Vigurs' slide pass from his own half and Sutton ran on to beat MacDonald in the left channel. The angle was tight but Sutton managed to squeeze the ball between McGhee and McKay and just inside the far post.
McFadden and Ainsworth had time to fit in more first-half efforts and Motherwell had a good chance to double their lead just after the break when Vigurs' brilliant first-time pass released Ainsworth but his touch allowed MacDonald to block.
McHattie, who had been struggling with a hamstring injury, came off for Jamie Walker, forcing a reshuffle at the back.
But Hearts dug deep into their limited reserves and somehow found the ammunition to put Motherwell on the rack.
Nielsen appeared to give them hope when he struggled with a Ryan Stevenson cross, which bounced off the bar, and then unconvincingly palmed away David Smith's long-range shot.
Hearts began to pepper him with shots from distance and he tipped over efforts from Stevenson and Walker, who saw another strike flash just wide.
Henri Anier, who signed a two-and-a-half-year contract on Friday, came on for the injured McFadden and had a shot saved on the break but Hearts kept up the pressure and Nielsen palmed away Paterson's close-range header before the Hearts teenager had another cleared off the line.
Anier had a goal disallowed with five minutes left when Sutton was correctly penalised for an aerial challenge after MacDonald had palmed away his header.
But Hearts created the final chance when they worked the ball to Hamill eight yards out. The midfielder forced a shot towards goal but Nielsen blocked with his feet.