All results were possible as the North One East game went into the final minute with Heath leading 24-21, but it was Cleckheaton who had the final word with Hainsworth’s try and a Dale Breakwell conversion giving them the win they craved.
They have now moved four points ahead of Heath and are just two points behind top two Ilkley and Driffield, making it an exciting end to the season.
Cleck, who had Olly Depledge returning at scrum half, Dom Flanagan on the right wing and Jack Marshall at full-back, were quickly into their stride and went ahead after only three minutes when Mike Hayward went on a good run and Hainsworth was in support to take the ball and score the first try.
A second score followed as Dom Flanagan’s clearance kick forced a drop-out and from it the ball fell into the hands of Dale Breakwell who landed a drop-goal from 45 metres out.
Heath were on the board through Eddie Cartwright’s penalty and they added a try soon after when keeping the ball alive through multiple phases with Jon Cole scoring to make it 8-8.
The visitors lost Josh Plunkett to the sin-bin, but despite the numerical disadvantage they went back in front after good work down the right by Dom Brambani and Flanagan led to a try from Brad Marsden. With Dale Breakwell adding the goal it was 15-8.
A frantic finish to the first half, however, saw Cartwright kick a penalty for the hosts and Pilcher score a try that was converted by Cartwright to turn the game round with Heath 18-15 ahead at the break.
Cleckheaton made a good start to the second half and levelled with a Dale Breakwell penalty.
He was on target again with another kick from longer range six minutes later to nudge the visitors ahead.
Heath struggled to make the same headway they had in the opening half, but stayed in the game and it was all square again as Cartwright landed a penalty.
A 50-metre penalty by the same player gave the home team a 24-21 lead with just five minutes to go, but Cleck were not done.
They hammered away at the Heath line in the closing stages and were rewarded with a minute left as Hainsworth powered over for his 15th try of the season and Dale Breakwell tagged on the extras.
There was time for a restart, but Cleckheaton drove the ball in and when Brambani hoofed the ball off the pitch they had completed a terrific victory, which was their ninth in their last 11 matches.
This Saturday they are back at home when a potentially dangerous Pocklington side visit Moorend for a game kicking off at 3pm.