Simon Kerrigan took seven wickets as Lancashire went top of the LV= County Championship Division Two table with an eight-wicket victory over previous leaders Northamptonshire at Wantage Road.
Kerrigan returned magnificent figures of 7-63 as Northants were bowled out for 241, James Middlebrook top-scoring on 75 to set Lancashire a target of 110.
The visitors wrapped up the win thanks to Andrea Agathangelou's unbeaten 57 to move a point clear of their opponents with a game in hand.
Northants began the day on 123 for four, requiring nine runs to make their opponents bat again, with Middlebrook resuming on 46 and Andrew Hall on three.
Middlebrook comfortably completed his second half-century of the matches the fifth-wicket pair survived the first hour of the day without any alarm.
Former South Africa all-rounder Hall went through 10,000 first-class runs in the process but Middlebrook gave his wicket away by needlessly launching Kerrigan to Kyle Hogg at deep square-leg.
Kerrigan completed his third five-wicket haul of the season and his ninth in first-class cricket when Agathangelou took a sharp one-handed catch at short-leg to dismiss Matthew Spriegel.
The England Lions spinner then claimed his third wicket in four balls when David Willey was also taken by Agathangelou at short-leg to depart for a golden duck.
Kerrigan took his tally to seven by trapping Northants wicketkeeper David Murphy lbw, meaning four wickets had fallen for 12 runs.
However, Hall, who needed a runner after a muscle strain, registered a fifty in the afternoon.
Lee Daggett plundered 11 before he was bowled by Lancashire captain Glen Chapple and Hall was the last to fall on 57 when he was superbly caught and bowled, one-handed, by the same man.
Chasing 110, Lancashire lost Karl Brown in the second over when he edged the first ball he faced to Middlebrook at first slip off Muhammad Azhar Ullah.
Middlebrook then pinned South Africa batsman Ashwell Prince lbw as Lancashire reached tea on 30 for two - still requiring another 80 runs.
But any doubts the visitors may have had were eased by Agathangelou racing to a half-century in just 61 deliveries with opener Luis Reece contributing 40 not out.
The winning run came via Agathangelou running a single off Daggett as Lancashire took a big step towards a return to Division One.