Whiteleas and Harton now find themselves 32 points behind the Readers Durham Cricket League Division Two leaders Littletown, after their derby loss away at Marsden.
Leas batted first and made only 135, mainly thanks to Scott Oliver with 49 not out, who led the recovery from 52-6.
Sura Malinga (4-29) and Andrew Ainsley (3-16) had them in all sorts of bother.
The home side then knocked off the runs for the loss of only six wickets, with Connor Elliott with (60) and Sura Malinga with (33) steering them home.
Abdul Ameer took 3-42 and Nick Quinn 3-33.
Boldon remain third in the Dukes ECB NEPL First Division, 31 points behind leaders Sacriston, after their home win over Burnmoor.
The visitors made 198-9 with Steven Meek (57) and Neil Young (56) top scoring.
Umar Waheed with 4-43 and Calum McCloud with 4-36 bowled very well.
In reply, Nicholas Sampson-Barnes with 60, Calum McCloud with 48 and Oliver Sampson-Barnes with 41, guided their team home by five wickets for an important victory.
Elsewhere in the Northumberland League Division One, Hebburn put in a great team performance to grab a good win against Monkseaton.
In a rain-affected game reduced to 35 overs, Monkseaton got off to a good start with opener Buttler scoring 30 before he was dismissed by Nick Whitehead.
Paul Cox then bowled an excellent spell to restrict Monkseaton, finishing with figures of 5-41 to leave Hebburn a target of 167 to win.
Hebburn got off to a steady start with Aidan Berry and Gary Taylor steering them to 30-0.
Whitehead then started to raise the run rate with some boundaries, but Hebburn then lost a few middle order wickets to bring Lee Tatum to the crease.
Tatum blasted some big sixes to get Hebburn to the finish line and finish on 47 not out with five wickets and seven overs to spare.
Whitburn succumbed to a six-wicket defeat in their Dukes NEPL Premier Division trip to Hetton Lyons.
Opener Daniel Shurben top-scored with 44 as the Villagers were all out for 149, with Ross Carty adding 32. Four Lyons bowlers took two wickets apiece to set up their victory push.
Chris Martin’s unbeaten 67 proved decisive, backed by 34 from Rob Talbot and 30 from pro Mahesh Rawat. Ian Elliott (2), Craig Smith and Mark Elliott took the wickets to fall as Lyons reached their target for the loss of four wickets.
South Shields, meanwhile, went down by 102 runs to visitors Stockton.
The Teessiders posted 199-9 batting first, with openers Tom Hewison (62) and Allan Worthy (60) dominating the Shields bowlers. Matthew Muchall and Sam Embleton, though, got on top to end with fine hauls of 3-47 and 4-60, with Chris Stewart striking twice.
Shields, though, never got to grips with the run chase and were bowled out for 97, with openers Tim David (24) top-scoring, with only Embleton (18), Stewart (16) and Michael Dunn (11) reaching double figures.
Ryan Buckley bagged 5-25 to lead Stockton home.