A stunning 58-ball century, which inspired a remarkable victory for Marton as leaders Hartlepool fought to save themselves from defeat, has left the title
to be decided in the final two games.
His fellow opener Neil Russell then took over the bowler bashing to finish unbeaten on 69 from 71 balls as the target was reached with six overs and five balls to spare.
The Indrasiri onslaught, his second successive century, made it possible for Marton to enjoy an astonishing seven-wicket victory.
Hartlepool dropped vital points at Normanby Hall where they could have won or lost, but settled for a draw. They retain ten of their 18 points advantage over Marton.
Pool again relied heavily on professional Kasun Bodhisha, whose top score of 44 took his season's run making in the league to within 36 of becoming the first to reach the 1,000 milestone.
Fellow Sri Lankan Janaka Gunarathne, playing against his old club, took three wickets as Pool reached 178-7. He hit a half century to leave Normanby needing 47 for victory with six wickets in hand,
only to see his side lose their way before finishing on 170-8.
Richmondshire's match with Darlington was washed out just short of the half-way point. Quakers hit 201-2, with Rajin Saleh falling ten runs short of his
second century, before the match was abandoned.
Middlesbrough's gloom turned to joy when they beat bottom club Northallerton from the penultimate ball and put themselves safe from relegation. They are 30 points clear of second bottom Bishop
Auckland who suffered another abandonment due to the weather and find themselves plunged 15 points from safety.
Boro made 244-9 with Paul Johnston contributing 46 on his return in an opening stand of 74 with James Lowe (39). Dan Hodgson then hit 56. Northallerton crumbled to 82-5 before Danny Luck (51 not
out) led a recovery to reach 164-6.
But the last four wickets added just seven runs and they were all out needing to survive just two final balls. James Burke (5-38) and Shahid Mahmood (3-29) were the Boro match winners.
Marske (209 all out) with 88 for Simon Guy grabbed a 14-point winning draw against Great Ayton (181-6) and gave themselves added hope of survival.
Star bowler of the day was Stokesley's new South African pro Gurshwin Rabie who took 8-48 against Billingham and has
23 wickets in four games since his arrival.
With the rain moving into the region to blight the programme, many matches became an object in trying to salvage as many points as possible.
Just a mile away from Emirates ICG, where England and India were washed out, Chester-le-Street managed to come within a couple of wickets of forcing
a win over South Shields in the NEPL.
But even though they failed to squeeze out victory they took a 16-point haul which sent them five clear of a frustrated South North.
An opening stand of 103 between Simon Birtwisle (44) and Quentin Hughes (56) set the Cestrians up for a score of 243-9 in 52 overs, but with 177 minutes of play lost in all, there was only time to
get to the vital 25 over mark in the Shields innings by when they had crumbled to 47-8, Richard Waite (4-25) and Andrew Smith (3-10) on fire.
II the Durham Senior League, Kimblesworth and Boldon each notched up 11 points from their truncated games and it left the newcomers with a 12-point lead to take into the final round of fixtures
Boldon put on 211-8 in 46 overs, Michael Walker hitting 11 fours in his 65, but South Hetton proved stubborn opponents and ended on 119-4 in a match that had no fewer than six interruptions.
Two hours playing time was lost at Felling where Kimblesworth declared on 225-3, Sam MacPherson, Craig Burke and Paul Craig all making half centuries. Their hosts had limited time at the crease and
closed on 45-2.
There was only 40 overs of play - but a big result for Seaham Park in the Durham Coast League as they bowled Silksworth out for 75, with Ali Watson (3-12) and
Alex Ludlow (3-25) leading the attack. The runs were knocked off in 16 overs for the loss of five wickets and victory took the Park 10 points clear of Boldon CA with one to play.
Just one game was completed in the NTSL, but Sacriston's eight-wicket victory over Ashington was enough to take them top, Swalwell's rained off draw with Chopwell earning them just nine points.
Kendal Ballard (3-16) and Ryan Moralee (3-29) helped put Ashington out for 113, and Melvyn Betts cracked 36 quick runs power Sacriston to a win inside 17 overs, and with it the league leadership.