Sewerby took a massive step towards the Division Two title after digging deep for a two-wicket win at second-placed Cayton 2nds.
The home side batted first and fine knocks from Simon Glave and Simon Stubbs with 55 and 56 respectively steered them to 182-7 from their 45 overs. Ash Porter took 3-35 and Calvin Roche 2-38 for the visitors.
Openers Dan Artley (36) and skipper Ian Dennis (48) laid the foundations for the visitors, but Cayton’s bowlers Glave (2-22) and skipper John Crowe (3-8 in four overs) dragged them back into contention.
Stalwart Robin Coates’ unbeaten 43 saw him keep his nerve and steer Sewerby home with two wickets and two overs to spare.
Third-placed Scalby 2nds kept the pressure on Cayton 2nds with a 34-run home win against struggling Staxton 2nds.
Teenage opener Edward Hopper hit a crucial 62 from 110 balls as Scalby posted 210-6, sharing a 43-run stand for the third wicket with Daniel Gregory (27) and a 46-run partnership for the fourth wicket with Matthew Tissington (20).
Youngster Luke Howland (42no from 34 balls) and veteran Adrian Hollingsworth (21no from 21 balls) shared an unbeaten seventh-wicket stand of 60 for Scalby Andy Holtby, Kieran Walker and Craig Hill took two wickets apiece for the visitors.
An excellent spell of 4-40 from Mike Buttery sent Staxton crashing to 58-5, but a superb stand of 112 for the sixth wicket between Walker (46) and Holtby (62) gave the away team hope, but they ended on 176-6.
Wykeham 2nds kept their promotion hopes alive with a superb run-chase to win by two wickets at basement club Pickering 3rds.
Veterans Les Welburn (49) and Graham Jemison (39) steered the Pikes to 212-6, James Wilson taking 4-34.
Fine knocks from Andrew Shepherdson (44) and Ian Thompson (36no) steered Wykeham home with three balls and two wickets to spare.
Ebberston 2nds kept their survival hopes alive with a 51-run success at Wold Newton.
Opener Jordan Welford and skipper Jake Finnegan struck 33 apiece for the visitors, the tail wagging to help Ebberston post 145-9.
Thomas Southwell (3-28) and Koppy Harrison (2-37) shone for the home side.
Harrison top-scored with 22 in reply, but superb bowling from George Hardie (3-12), Jon King (3-21) and Sean Perryman (2-11) sent Newton crashing to 94 all out in 40 overs.
Seamer 2nds’ promotion challenge was dented by their eight-wicket hammering by Snainton.
Fine knocks from Dave Graham (61) and Tom Greenwood (45), allied with 28 from Dan Jewitt, saw Seamer post 175-9.
Michael Kipling was the top Snainton bowler with 3-24, Rob Holt and Leigh Watson taking two wickets each.
Kipling also shone as an opener with the bat, his unbeaten 70 guiding Snainton home with six overs and eight wickets to spare, with solid support from Joe Barker (36) and Ben Norman (49no).
Mulgrave 2nds strengthened their grip on top spot in Division Three with a 145-run home win against 10-man Folkton & Flixton 3rds.
Chris Spenceley fell agonisingly short of three figures on 98, while Martin Thistle hit 58 as the hosts posted an imposing 245-9 from 40 overs. Alex Potter took 3-25 for the visitors.
Flixton were dismissed for 100, skipper Jamie Thistleton top-scoring with 15, as Dominic Ingham bagged 4-29 and Ben Duell 3-12 for the leaders.
Grosmont stayed in second place after a 58-run win at Muston.
Arran Liddle hit 29 for the visitors, while Chris Pickering and David Bowes struck 25 apiece as Grosmont were dismissed for 187, Mathew Atkinson bagging 3-51.
Phil Robson hit 29 and Rikki Lawrence 27 to give Muston hope, but an excellent spell of 5-29 from Brinton Darnell and 3-49 by Liddle saw the hosts dismissed for 129.
Nawton Grange 2nds are only a couple of points behind Grosmont after receiving 22 points when Heslerton 2nds failed again to raise a team.
Ravenscar strolled to a 10-wicket win at Filey 2nds to keep their own promotion aspirations alive.
The home side were skittled for 85, Stu Neilson top-scoring with 34, Jon Nelson taking 2-2, with two wickets apiece also for Babu Mathew, teenager Hayden Williamson and Freddie Barker.
Ravenscar knocked off the runs without loss from only 16.1 overs, Joe Bayes hitting 50no and Williamson 22no.
Oli Varey took an amazing 8-27 as Malton & Old Malton 3rds won by 163 runs at Ganton 2nds.
Chris Bingham smashed 75 and Ali Blacklee 39 as Malton posted 232-6, Eddie Bradley taking 3-27.
Varey then shone as Ganton slumped to 69 all out.
Sherburn 2nds won by five wickets at home to Brompton 2nds to stay third in Division Four.
Ben Atkinson hit 60no and Steve Johnson 33 as Brompton posted 141-7, Ash Oldroyd taking 3-42 and Nick Dobson 2-20.
Skipper Matthew Lickes hit 36, while Gareth Driver, on loan from Heslerton, and Jordan Farrow, hit 29 apiece as Sherburn sealed the win. Tony Hulme took 3-27 for the visitors.
Scalby 3rds cruised to an eight-wicket win at home to Thornton Dale 2nds.
Scott Wilson took 4-18 and Stephen Shannon 3-23 as Dale slipped to 80 all out, Jon Cooper top-scoring with 33.
David Thomas (37) made sure of the Scalby win.
Scarborough RUFC, Ravenscar 2nds and Cayton 3rds were handed full points as Forge Valley 2nds, Pickering 4ths and Malton & Old Malton all failed to raise a team and conceded.