With two games remaining, Streethouse have a commanding 15-point lead over sole rivals Frickley Colliery whose title hopes faded when they lost at Ackworth.
Paul Langley (43), Martin Rhodes (33) and Paul McMullan (33) guided Streethouse to 180-6.
Leg spinner Richard Sykes bagged 5-5 in a sizzling four-over spell to send Old Sharlston collapsing to 78 all out in reply.
Ackworth boosted their chances of pipping Hooton Pagnell and Fishlake for third place by completing a league double over Frickley.
Chris O'Grady (78), Richard Young (36), Kevin Booth (31) and Kevin Marshall (24) steered Ackworth to 204-9.
Lovepreet Singh was Frickley's most successful bowler with 4-51.
Frickley's reply was led by Steve Secker (70), Richard Belk (27) and Shane Payne (25).
They were left needing seven runs for victory off the final over but managed only three and closed on 201-9.
Ackworth's main wicket-takers were Craig Walker (3-40), Marshall (2-45) and Jordan Harvey (2-33).
Featherstone have lingering relegation worries after losing at lowly Wombwell Main.
Nick Frankland (28) was the only batsman who made an impact as Featherstone were bowled out for 136 by Joe Ashurst who snapped up 5-32 from 14 overs.
When Wombwell replied, Jamie Robinson kept Featherstone in the game by claiming 4-46 from 11 overs but the home team eventually scraped a two-wicket victory, with Matthew Tonks (35) an important contributor.
Featherstone are 14 points ahead of second bottom Sandal who improved their chances of avoiding the drop with a three-wicket success at Crofton.
Amijid Sadiq (5-29) and Tom Martindale (3-27) restricted Crofton to 153, which included 33 from Colin Scattergood.
Kristian Shuttleworth (67) led Sandal's successful reply, despite the efforts of Crofton's Chris Cooper who took 5-36.
Bottom side Stainborough look doomed to relegation. They are 15 points adrift of safety after losing by 41 runs at Hooton Pagnell.
Opener Ian Jackson hit the top-flight's highest individual score on Saturday with an unbeaten 112. Ian Taylor chipped in with 35 as Hooton racked up 203-6.
Craig Toyne grabbed 3-46 and Alywin Dyke 3-43 as Stainborough were bowled out for 162 in reply. Their top scorer was Bobby Londt with 47.
Lee Johnson (35), Andy Shelton (31) and Paul Moores (3-29) led Fishlake to a 41-run win at Sprotbrough whose defeat was hard on all-rounder Karl Buxton (6-33 and 25).
Saturday's Pontefract League results were:
Division 1: *Ackworth 204-9 (C O'Grady 78, R Young 36, K Booth 31; L Singh 4-51), Frickley Colliery 201-9 (S Secker 70, R Belk 27, S Payne 25; C Walker 3-40); *Crofton 153 (C Scattergood 33; A Sadiq 5-29, T Martindale 3-27), Sandal 154-7 (K Shuttleworth 67; C Cooper 5-36); *Hooton Pagnell 203-6 (I Jackson 112no, I Taylor 35; P Kershaw 3-14), Stainborough 162 (B Londt 47; A Dyke 3-43, C Toyne 3-46); Streethouse 180-6 (P Langley 43, M Rhodes 33, P McMullan 33), *Old Sharlston 78 (R Sykes 5-5); Fishlake 204 (L Johnson 35, A Shelton 31, M Mason 29, N Morley 29; K Buxton 6-33, G Bright 3-62), *Sprotbrough 163 (K Buxton 25, B Lyons 25; P Moores 3-29); Featherstone 136 (N Frankland 28; J Ashurst 5-32), *Wombwell Main 138-8 (M Tonks 35; J Robinson 4-46).
Division 2: Thorne Colliery 115-9 (D Longley 5-30), *Askern 118-3 (D O'Grady 50no, A Lunn 42; M Walton 3-16); *Barnby Dun 160-8 (S Rich 32; N Brewer 3-21), Upper Haugh 161-7 (R Oxberry 42; C Broughton 3-36); Conisbrough 303-4 (P Green 83, J Phillips 65, P Hemmingway 43; J Blacker 3-58), *Frickley 164 (R Wincer 55; C Jackson 3-85, D Ward 3-10); Darton 192-6 (C Lee 71, L Baxter 35; C Dixon 3-51), *Monk Bretton 195-5 (S Laughton 47, D Whitfield 45, L Clayton 37; G Kilburn 28; N Worsley 3-21); *South Kirkby 176-8 (J Scott 67, Dean Woolsey 27; S Danby 3-37, P Wood 3-48), Rothwell 109 (S Danby 47; S Scott 6-36); *Whitley Bridge 280-9 (S Vaux 108, E Wilson 38, G Draper 33), West Bretton 140-6 (D Wood 36; C Walton 3-36).
Division 3: *Fairburn 178-9 (J Clegg 42; A Warren 5-48), Yorkshire Main 157-9 (M Spavin 59; G Bancroft 4-36); *Hemsworth 116 (D Whelan 5-37), Allerton Bywater 118-6; Thurnscoe 246-6 (D Whitehurst 100no), *Stainborough 156-8 (A Gilfillan 45); *Darton 210-4 (J Morley 56, D Hawley 48no), Ryhill 174-9 (L Turner 48no); *Fishlake 150-8, Hensall 151-5 (J Espley 35); *Hundhill Hall 135, Sykehouse 125 (P Sanders 56); Whitley Bridge 164-9, *Knottingley 165-4 (N Kirton 57); *Normanton 156-7 (S Goodwin 76no), Ackworth 115-7 (M Beckett 3-7); Old Sharlston 137-7, *Streethouse 130 (M Robinson 50; D Keating 5-29); Glasshoughton 218-5, *Conisbrough 222-5 (T Kelly 58, M Neale 56, M Barnes 55).
Division 4: Barnsley 83, *Pledwick 84-0; Crofton 169-8, *Sandal 96; Ferrybridge 156, *Featherstone 83; *Upper Haugh 296, Hooton Pagnell 113; South Kirkby 162-9, *Thorpe Audlin 162-7; *Hensall 130-9, Sprotbrough 109.
Division 5: Barnby Dun 171-9, *Yorkshire Main 174-7; *West Bretton 175-7, Hundhill Hall 89; *Allerton Bywater 83, Knottingley 84-3; *Royston 135-8, Monk Bretton 83; Pledwick 116, *Bentley Colliery 117-3.
Division 6: Eggborough PS 80, *Ryhill 82-9; *Thurnscoe 189-6, Fairburn 117; Normanton 155-7, *Ferrybridge 83; *Sykehouse 145, Thorpe Audlin 88; *Glasshoughton 111, Wombwell 112-3.
League placings:
Division One: Streethouse 151, Frickley 136, Hooton Pagnell 122, Fishlake 120, Ackworth 119, Sprotbrough 104, Old Sharlston 101, Crofton 98, Featherstone 93, Wombwell 85, Sandal 79, Stainborough 70.
Division Two: Conisbrough 145, South Kirkby 123, Barnby Dun 121, Whitley Bridge 117, Monk Bretton 117, Rothwell 112, Darton 107, Upper Haugh 103, Askern 86, Frickley A 78, Thorne 73, West Bretton 73.
Division Three (East): Fairburn 159, Ackworth A 136, Yorkshire Main 130, Conisbrough A 116, Hensall 108, Knottingley 107, Hundhill Hall 100, Fishlake A 83, Whitley Bridge A 71, Sykehouse 64.
Division Three (West): Thurnscoe 129, Allerton Bywater 124, Glasshoughton 122, Normanton 110, Darton A 106, Stainborough A 103, Ryhill 101, Streethouse A 89, Hemsworth 86, Old Sharlston A 80.
Division Four: Upper Haugh A 139, Pledwick 132, South Kirkby A 126, Thorpe Audlin 116, Ferrybridge C 107, Sandal A 105, Sprotbrough A 101, Hooton Pagnell A 96, Hensall A 89, Crofton A 89, Featherstone A 85, Barnsley 84.
Division Five: Monk Bretton A 142, Royston Old Town 126, Bentley Colliery 118, Barnby Dun A 117, Pledwick A 106, West Bretton A 98, Yorkshire Main A 89, Knottingley A 83, Hundhill Hall A 70, Askern A 49, Allerton Bywater A 26.
Division Six: Thurnscoe A 156, Wombwell A 141, Fairburn A 130, Normanton A 114, Rothwell A 113, Eggborough PS 97, Glasshoughton A 89, Hemsworth A 88, Ryhill A 84, Sykehouse A 81, Thorpe Audlin A 70, Ferrybridge A 69.