A superb 99 from in-form batsman Mike Artley helped Division Two leaders Sewerby earn a 44-run success at Snainton.
Artley smacked 12 boundaries in his knock, falling agonisingly short of making it to three figures.
Calvin Roche weighed in with an unbeaten 33, while Peter Davies added 27 and skipper Ian Dennis 24 as the visitors posted 248-5. Leigh Watson was the top Snainton bowler with 3-66.
Opener Michael Kipling hit a steady 50 to keep Snainton in with a chance of chasing down their target, but, despite a superb swift knock of 58 from all-rounder Watson, including six fours and three sixes, and 27 from Richard Cook, the hosts ended up on 204-7.
All-rounder Roche, youngster Ted Traves and spinner Craig Ward ended up with two wickets apiece to steer Sewerby to another victory as they look to secure a spot in the first division.
The leaders are now 68 points clear of second-placed Cayton 2nds, who suffered a 76-run loss at promotion rivals Wykeham 2nds.
Cayton looked to be heading for another win which would tighten their grip on second spot after limiting Wykeham to just 119-6 from 45 overs.
Stalwart Pete Shepherdson hit 37, Ian Johnson 27 and Andrew Shepherdson 20 for the home side, with Lee Pettitt (2-18) the star bowler for Cayton.
But the visitors then crumbled to 43 all out in reply after tea from 24.3 overs, with only seasoned campaigner Steve McAleese (18) making it into double figures.
The three-pronged bowling attack of Liam Eyre (4-11), Daniel Bateson (3-19) and David Stockhill (3-6) shone.
Third-placed Scalby 2nds missed out on a huge chance to jump into the second promotion place after their shock 33-run reverse at Wold Newton.
Opener David Southwell hit 30 and number seven bat Karl Ridsdale an unbeaten 37 as Newton posted 134-9 from 45 overs, number 10 batsman Mathew Atkinson weighing in with what turned out to be a crucial 19.
Youngster Luke Howland took 3-24 for the visitors, James Scott 3-35 and Tony Geall 2-25.
Lee Kerr led by example in reply with 30, but the only other Scalby batsmen to make it to double figures were Daniel Gregory (18) and veteran all-rounder Adrian Hollingsworth (15), as they were dismissed for 101.
Mark Holtby took 3-15 from 12 overs, while James Knaggs grabbed 3-24 from 12 overs, Atkinson capping a fine all-round day with final figures of 2-28.
Staxton 2nds boosted their chances of beating the drop with a four-wicket home win against basement club Pickering 3rds.
The 10-man visitors were dismissed for 98, youngsters Luke Shepherd (35) and George Hodgson (24) the top-scorers for the Mill Lane-based club.
Craig Hill was the leading bowler for Staxton with 3-26, while Joe Stearman, Ryan Hargreaves and Kieran Walker claimed two wickets apiece.
All-rounder Hargreaves then struck a crucial 38 to lay the foundations for a successful run-chase for Staxton, Walker’s unbeaten 15 securing the win for the home side and improving their chances of beating the drop.
Macauley Gibson (3-37) and Shepherd (2-16) tried their best to keep the Pikes in the contest.
Seamer 2nds’ promotion hopes were dented as their game at lowly Ebberston 2nds was washed out.
Division Three was badly hit by the wet weather on Saturday, with Folkton & Flixton 3rds v Muston, Ganton 2nds v Mulgrave 2nds and Nawton Grange 2nds v Malton & Old Malton 3rds all being cancelled on the morning due to the rain.
Grosmont moved back into second spot, and into promotion contention, thanks to their scheduled opponents Filey 2nds failing to raise a team and conceding the match.
Ravenscar were also handed 22 points as basement club Heslerton 2nds conceded for the sixth time in 13 match weeks.
Scarborough Rugby Club continued their domination of Division Four with a four-wicket win in a low-scoring affair at Silver Royd against 10-man Wykeham 3rds.
The game looked to be drawing to a swift conclusion when Wykeham slumped to 16-5 thanks to Matty Jones and Mark Kelly, who recorded 2-7 and 2-6 respectively from their five-over stints.
Lewis Eustace’s 47 from 63 balls then saw Wykeham all out for 87, as Brett Canham also took 2-6.
Eustace also impressed with the ball, bagging 2-16 as the hosts hit 91-6 from 23.4 overs, Jones hitting 24 as the leaders stretched their lead over second-placed Great Habton to 33 points.
Scalby 3rds remain in promotion contention after their four-wicket home win against Flamborough.
Stan Jackson took 4-46, with two wickets each from Nathan Barber and Robbie Kerr helping dismiss Boro for 155.
Marcos Brown-Garcia hit 44, J Vincent 30 and skipper Mark Abram 25 for the visitors.
Stuart Rowland (26) was the only home batsman to get going as Scalby sank to 81-6, but an unbeaten seventh-wicket stand of James Wainwright (44no from 29 balls) and David Grace (29no from 29 balls) saw Scalby home, as Brown-Garcia took 3-39 for Boro.
William Wood’s brilliant unbeaten 90 helped Cayton 3rds win by eight wickets at home to eight-man Forge Valley 2nds.
Mick Glew rolled back the years with a cracking knock of 89, Steve Boyes weighing in with 54 as the Ayton club posted an impressive 190-6.
Cayton then made the most of the three men missing in the field, Wood leading the way with a powerful 90no and Michael Pennock (34no)adding his support.
Brompton 2nds eased to a nine-wicket win at Thornton Dale 2nds.
Luke Harper took 3-28 for Brompton as Dale posted 126-9, Ron Lee hitting 41 and Andrew Snaith 27 not out.
Chris Suggitt (52no) and father Steve (35) shared an opening stand of 98 as Brompton eased home.
Pickering 4ths conceded their game at home to Malton & Old Malton 4ths.