Promotion-chasing South Shields produce a scintillating away performance
Heaney struck two brilliant goals - one of which came from the centre circle - to cap an outstanding display at Mount Pleasant.
Darius Osei had earlier fired the Mariners in front and captain Blair Adams capped things off with a terrific strike just after the hour mark as Shields extended their unbeaten record to nine games.
Kevin Phillips' side are nine points clear at the top of the Pitching In Northern Premier League heading into their final 10 fixtures.
On a difficult surface, both teams struggled to create opportunities in the opening minutes, although the lively Donald Chimalilo dragged a shot wide from 20 yards for the hosts and Osei charged down a goalkeeping clearance at the other end before the ball bounced wide.
The Mariners dominated possession and began to strengthen their grip on the encounter around the 20-minute mark.
A warning sign was flashed when a flowing move featuring Heaney saw Lewis Alessandra fed on the left of the area before he sent a dangerous ball across the face of goal which was scrambled clear.
The hosts needed goalkeeper Oliver Swan to save them from the resulting Heaney corner as he produced an outstanding reaction stop to keep out Osei's header.
Promotion-chasing South Shields continued to probe and were rewarded on 34 minutes when Jordan Hunter delivered a superb cross and Osei muscled in front of a defender before prodding into the bottom corner.
Heaney was at the heart of much of the visitors' bright play and he lit up the match further three minutes before half-time with a goal of the season contender.
After nudging the ball past an opponent near the halfway line, Heaney went for goal from the centre circle and sent a stunning effort beyond a sprawling Swan and into the net to double Shields' advantage.
The result did not look in question from there, but the attacks kept flowing for Shields and eight minutes into the second half, they almost had a third when Dylan Mottley-Henry took the ball past Swan before having a strike cleared off the line.
Mottley-Henry was then denied by a fine Swan save before Heaney added a second to his tally, bringing the ball onto his left foot before caressing the ball into the bottom corner from 20 yards.
The scoring was completed just after the hour mark as captain Adams ruthlessly fired into the net via the post after a clip down the left of the area by Robert Briggs.
It will go down as one of Shields' most eye-catching performances of an increasingly impressive campaign, and Kevin Phillips’ side will aim to continue the momentum when they travel to Matlock Town on Tuesday.
South Shields: Boney, Hunter, Adams (c), Liddle, Broadbent, Smith (Woods 62), Heaney, Briggs, Osei, Alessandra (Shokunbi 78), Mottley-Henry (Mongoy 72). Subs not used:
Goals: Osei (34), Heaney (42, 58), Adams (61).