Needing a point to seal promotion, they saw off their relegation-threatened hosts 3-1 for their 25th win in 29 games.
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They will be crowned champions on Saturday if Rossendale don't beat Southport Hesketh.
After a cagey start, Danny Ormerod broke the deadlock before Isaac Loftus and Josh Sanda struck twice in the space of three second half minutes to put Lostock out of sight.
Aaqil Campbell pulled one back from the spot but Dixie Dawson's men couldn't be denied their moment.
Rossendale can still pip them to the title if they win all their games in hand but will need to win handsomely to overturn a 21 goal deficit.
For the second game running, they came from behind to win 2-1, this time seeing off Croston.
Jordan Freeman fired the hosts ahead but Rossendale restored parity before half-time through Simon Nangle.
Tom Walker hit the winner.
Hesketh Bank will be hoping Rossendale slip up and they kept their side of the bargain with a 2-1 derby win over Southport Hesketh.
In a game of few chances, Luke Smith prodded home at the second attempt to break the deadlock on 30 minutes.
Joe Smyth-Ferguson then capitalised on a defensive error to double the advantage. Matthew Coughlan scored a consolation in injury time from a 20-yard free kick.
Haslingden St Mary's beat Eagley 4-2 with goals from Ryland Casey, Lewis Hanley, Jack Cain and Dylan Harris.
In Division Two, Euxton Villa and AFC Blackpool Res played out a thrilling 4-4 draw.
Euxton went three up through an own goal and efforts by Lewis Pilgrim and Ryan Fox.
But goals either side of half-time by Ralph Threlfall Newton and Matthew Sillett made it 3-3.
Vaughn Green put Euxton back ahead only for Sillett to strike 10 minutes from the end to earn his side a share of the spoils.
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