Lancashire spinner Stephen Parry completed a first County Championship five-wicket haul to help beat reigning champions Middlesex by eight wickets.
Middlesex’s first Championship defeat since September 2015 brought to an end their unbeaten run of 21 games.
Dawid Malan (52) completed his half-century at Southport in helping to add 80 to the visitors’ overnight score as Middlesex were bowled out for 236.
Lancashire then eased to their target of 108, reaching 111-2 in 30.2 overs.
They are now fourth, 16 points off the top and 41 points clear of danger after recording only their second Championship win of the season, with over a session to spare – and, despite the loss of the entire second day to rain.
When Middlesex resumed their second innings on 156-6, hopes of avoiding defeat rested largely with Malan. But he was eighth man out, the second of two wickets for Ryan McLaren (3-48).
England limited-overs international Parry, playing in only his 16th first-class match at the age of 31, then finished Middlesex off to return figures of 5-45.
After removing Tim Murtagh, Parry picked up his fifth wicket, when he trapped Roland-Jones lbw for a very entertaining 31 off 32 balls – to complete his first ‘five-for’ in first-class cricket since his debut against Durham UCCE 10 years ago.
England Test opener Haseeb Hameed, who has shown a return to form in this match after a run of six successive failures, was still there at the end after a characteristically patient 38 from 81 balls, partnered by skipper Steven Croft on 34.
That followed a lively 22 from Liam Livingstone, who marked his call-up to England’s squad for the three-match T20 series against South Africa in a three-ball sequence which saw him dropped at second slip by James Franklin and hit on the gloves by Toby Roland Jones before edging one behind.
Lancashire and Middlesex are both back in Championship action next Monday (19 June), when the Red Rose host third-placed Hampshire at Old Trafford and Middlesex, in sixth, face second-placed Yorkshire at Lord’s.
Lancashire head coach Glen Chapple told BBC Radio Lancashire:
“We faced a challenge after losing to Yorkshire and we’ve come through that brilliantly. The lads have put in a great team performance and defeated a team that haven’t been beaten since 2015 so we’re delighted with that.
“When you face your first loss of the season it’s always a mental challenge. You have result pitches at out grounds but to beat a good team like Middlesex requires a lot of work.
“Ryan McLaren is looking really solid with the bat and hits great lengths with the ball so both his areas are in good nick and he’s starting to really fire for us.”
Middlesex captain James Franklin told BBC Radio London:
“The run had to come to an end at some point. And we were totally outplayed by Lancashire for two and a half days. We’ve seen over the first five games that we’ve played this season that the standard in this division keeps getting better so we’ve got to move with that
“That’s the challenge for a team that’s won the title. At the moment, the pack have well and truly caught up and we’re not quite firing on all cylinders. We have to keep trying as hard as we can to dominate games and we’ve been dominated here by a team that has played better cricket.
“We were 50-60 runs light in the first innings and they were probably 50-60 runs over par and that was the difference. If we had been defending 200 or 220 obviously we would have been in a good shout of putting them under some serious pressure but that first innings was the real difference and we were never able to claw ourselves back.”