Dropped catches cost Marton the chance to stay in top place on a day when reigning champions Richmondshire became the fifth different team this season to take over as leaders.
The Dalesmen crushed once mighty Middlesbrough and did it so ruthlessly they had to wait over two hours to discover whether the victory would take them to the top for the first time.
Marton, who were locked in battle with fellow championship challengers Guisborough, might have stayed ahead had it not been for a nervy afternoon in which they dropped three crucial catches and then found themselves chasing a runs target much higher than it might have been.
They had to settle for a share of the points in a drawn finish after their batting became a redeeming feature. Their butterfingers nightmare saw Graham Murray dropped twice and go on to share a stand worth 83 with the home professional, Ranil Dhammika (42) who was also given a ‘life’.
Murray, who made 51 from 35 balls with four fours and three sixes, gave his first chance when he had only scored eight. With a 106 ball half century from opener Martin Hood, Guisborough finally posted a challenging 204 for six of which Marton fell short by 13 runs.
Marton got off to a flying start through Wally Ghauri (36) before two wickets fell on the same score. and Lee Hodgson (41) and JoeTate (38) revived their hopes with a 72-run partnership.
But four more wickets fell for just 26 runs and the chase to win was cushioned by a desire not to lose. With Danny Wade unbeaten on 25 they reached 191 for seven to save the game.
Opposing professionals Dhammika (3-32) and Upul Indrasiri (4-66) now jointly lead the bowling ratings with 29 wickets apiece.
Marton not only lost top slot but they were pushed down into third place after Darlington won for the fourth time in five games to move back above them.
They defeated Stokesley by 52 runs with just ten balls of their game remaining. A 93-run second wicket stand between Liam Coates (66) and John Watson (50) made sure they posted 184 despite four wickets for Andrew Weighell.
But those three tormentors of the best batsmen, Peter Armstrong (6-32), Doug Mulholland (2-43) and Jon Barnes (2-45) rattled through the home side after Tom Preece (44) had his resistance ended.
Richmondshire bowled out Middlesbrough for just 116 with Craig Swainston (5-35) and Craig Marshall (2-4) working in harmony as the successful strike force for a second successive week.
James Lowe (41) and Brett Roberts (28) took Boro beyond the hundred mark only to see the last six wickets fall for just 10 runs. Gary Pratt (48) and James Clarkson (40 not out) hurried Richmond to an eight wicket win in just 22.3 overs.
Great Ayton are 21 points behind the new leaders after slipping for a second week, unable to bowl out Redcar.
Their last two batters resisted for five overs to finish on 130 for nine, 43 runs behind Ayton for whom Nick Hendrie (56) and Chris Batchelor (48) were top notch. Muhammed Saad (5-45) and Tariq Aziz (4-49) starred for Redcar.
Saltburn are starting to impress following their promotion and won for a third time in a dramatic finish at Sedgefield. Sri Lankan ‘pro’ Umesh Karunaratne produced a magnificent 107 ball 77 run match winning innings which saw him hit a six off the game’s last ball to clinch the victory by four wickets.
His 97-run sixth wicket partnership with Kevin Brown (57 from 52 balls) turned the game upside down.
Sedgefield’s new professional Nisal Randika hit 82 and took two wickets on debut despite having only a day to recover from his long journey from Sri Lanka. Just as disappointed to lose was Martin Cull whose 17 overs cost just 18 runs.
Barnard Castle eased their worries with their first win for seven games at Thornaby where James Quinn and ‘pro’ Aamer Sajjad both scored centuries.
It was Quinn’s first and Sajjad’s second of a season which has now seen 15 scored in the 78 games played. Barney hit their top score of 254 for three with Quinn’s 116 from 132 balls and Sajjad’s unbeaten 100 from 102 balls.
Thornaby, now 19 points adrift as bottom club, were bowled out for just 147 with Quinn (4-30) man-of-the-match.
An unbeaten 92 from John Rickard and another five wickets for Marc Symington pushed Hartlepool closer to the title challengers but sent Normanby Hall (99 all out) back into a relegation place.