The basement boys bowled the side directly above them in the table out for just 104, Harris Egglestone (35 not out) then only visiting batsman to impress.
Bash Khan, Sajid Khan and Adil Shazad all contributed for Blubberhouses, taking three scalps apiece.
The top-flight’s bottom side made hard work of their run-chase, nobody managing more than opener Will Haines (29), but they eventually reached 105/7 despite the efforts of Mark Wood, who claimed a superb 6-25.
At the opposite end of the table, leaders Killinghall made it eight wins out of nine for the season courtesy of a six-wicket triumph at home to Arthington.
The away team were dismissed on 165, Alex O’Neill (42) their leading light as Dan Atkinson (3-35) and Hamish McIntryre (3-38) impressed with the ball in hand.
Runs from Ed Paxton (48) and McIntyre (41) then saw Killinghall to 169/4 with 3.2 overs to spare.
West Tanfield stay second having recorded their sixth success in seven attempts when they visited Helperby.
The hosts were blown away for 55 last time out and fared similarly badly on this occasion, heading back to the pavilion with only 66 on the board as Jonny Luty (3-8), Jake Stubbs (3-14) and Angus Shaw (3-24) caused all sorts of problems.
Tanfield then eased to 69/3 in 12 overs to wrap up a seven-wicket win.
Birstwith bounced back from their recent run of poor form, and in some style too.
William Johnston (108) smashed a stunning century, while Craig Robinson (82) and Jon Millward (54 not out) also weighed in as the hosts racked up a sizeable 318/7 from their 45 overs against Masham.
Craig Broadley knocked over three home batsmen, and although Sam Ambler (47) and Kieran Bramley (33) contributed with the bat, Masham were always up against it when they took their turn at the crease.
And with Millward (4-48) and Callum Halliday (3-18) bowling well, the away reply ended 201 runs short on 117.
Darley’s first-innings total of 252/4 proved more than sufficient to see off Harrogate 3rds.
Larry Audain led the way for the defending champions, plundering 136 not out alongside Adam Copeland (48).
Matt Ingham (57) and Oscar Murray (38) did their best to keep the Roosters in the match, however they would not progress beyond 169.
Rob Nelson was responsible for doing a big chunk of the damage for Darley, finishing the afternoon with figures of 4-19.
Mason Scopelliti (99 not out) came agonisingly close to making a ton as Pateley Bridge beat Kirk Deighton by 41 runs.
Gary Muff (52) was also in decent touch in the Badgers’ 279/5, Robert Barker scooping three wickets.
Richard Ward scored 85 not out when Deighton responded, with Gavin Mills adding 50 not out and Louis Toseland 41, though they closed on 238/6.