The championship will become a straight fight between Richmondshire and Darlington in what is set to be an exhilarating final fortnight after Marton dropped out of the race as they were beaten for only the second time all season.
But the league cup winners could still have a say in where the title goes as they have to meet the Dalesmen, leaders still by 16 points, at Richmond next Saturday.
Guisborough produced one of their best performances to end Marton’s slender hopes of staying in the hunt as one of the top three, while Richmond halted Middlesbrough’s run of ten games without defeat and the Quakers enjoyed a record 16th victory against Stokesley.
There was extra excitement at the other end of the table when Sedgefield beat Saltburn in a nail biting finish which was to guarantee their premier place for a third season.
The Seasiders had the misfortune to lose their professional, Umesh Karunaratne, to a freak accident while in a partnership worth 46 runs with Paul Allen which had taken their side to 78 for one.
The Sri Lankan, who was unbeaten on 25, slipped as he completed a run, fell awkwardly hitting his head heavily on the pitch and was unable to continue. After he retired to seek medical aid, Saltburn collapsed from 94 to 125 for nine as they lost eight wickets for just 21 runs.
Only Allen, who made 32 from 67 balls, looked comfortable as the spin of Nisal Randika caused problems. His seven wickets from 15 overs at a cost of just 24 runs was a season’s best.
Sedgefield were moving towards a vital success when rain and the sun combined to bring the game to a halt. The rain soon stopped but the sun behind the bowler’s arm was judged as a danger to the facing batsman so the game took longer to resume. And when it did, after four lost overs, the scramble for the win points became perilous.
The visitors lost five wickets for just 26, including four for four, and it needed the last two at the crease, Martin Lower and Martin Cull, to see them over the line. Apart from Lower (14 not out) and earlier Steve Naylor, top scorer with 40, only one other reached double figures.
There was also a massive batting collapse at Acklam Park where Middlesbrough on 92 for four were bowled out for 101. A first-ever hat trick for Craig Marshall, currently with the best average of any bowler in the league, saw Ryan Buckley (48), Brett Roberts and David Bruton perish.
The Dalesman finished with 5 for 29 from nine overs with Shani Dissanayake (2-29 from 10.4) making it a spin double.
Richmondshire romped to victory by nine wickets, their seventh in the last eight games, as Gary Pratt (57 from 106 balls) and James Clarkson (35no) put on 98 for the opening stand.
Darlington’s win was equally as comfortable, needing only 20.5 overs to score 104 for three to overpower Stokesley whose form has suffered another dip recently. Only Chris Allinson, unbeaten on 56 from 116 deliveries, and Will Brown (21 from 55 balls) offered resistance to Liam Coates (4-16) and Jon Barnes (4-21).
Coates (35no) and James Dobson (30 no) shared a stand of 45 to take the Quakers over the line after Allinson had claimed their first two wickets for just 13 runs but couldn’t capitalise further.
Marton had an unusually poor batting day against Guisborough’s Chris Nicholls (3-40) and Ranil Dhammika (3-38). They were restricted to 147 for seven with even Lee Hodgson (37) finding runs slow to come.
The Priory club won with eight wickets and ten overs to spare as Martin Hood (56no), Richie Evans (44) and Dhammika (41no) put an end to Marton’s 15-match unbeaten run.
Great Ayton’s entertaining batting counted for nothing as Redcar helped themselves to a five wicket win despite the absence of Muhammad Saad who has been allowed to return home early after an outstanding first season. Callum Brown (45), Tom Urwin (44), Tyler Easton (48no) and Omar Shahid (32) all responded following four wickets on premier debut for spinner David Corps.
Ayton’s trio of Nick Hendrie (60), Chris Batchelor (58) and Steve Pennock (51) had set them up at 209 for six, but it didn’t phase the Seasiders who scored 75 from the last 12 overs for victory.
Relegated Thornaby (87 all out) lost for the 17th time at Barnard Castle where Ben Usher hit an unbeaten 65 and James Finch grabbed 6-33.
In the match at Redcar, Normanby Hall became the second team to have their relegation fate sealed when they were bowled out for just 86 as the Symington boys, Craig (6-50) and Marc (4-14) showed no brotherly love to their opponents.
Hartlepool then made careful progress towards their seven wicket victory, taking 36.3 overs to reach the modest target with the siblings featuring again as Craig (31 not out) and Marc (27) did the bulk of the run scoring.