Greg Mann led Main to their second successive victory with an unbeaten 93 as they chased down the home side’s total of 221-7 with three overs to spare.
Andrew Gardiner (52) and Scott Wood (49) also made important contributions with the bat.
David Barrett (94) and Suliman Ahmad (60) had earlier impressed for Barnby Dun, who replace Rossington at the foot of the table.
Hooton Pagnell suffered a surprisingly convincing defeat at home to Hatfield Town.
The hosts suffered an almighty collapse to end up back in the pavilion for 84.
Openers Luke Lodge (24) and Callum Howie (25) had made a steady start but no one else reached double figures and the last seven batsmen could only muster three runs between them.
Kevin Marshall bowled excellently to claim 5-20 and James Winstanley took 3-14.
Hatfield’s Paul Davies made 48 as the visitors coasted to a seven wicket victory in just 14 overs.
Askern Welfare slipped closer to the drop zone after a 168-run defeat at West Bretton.
Only Ross Adamson (26no) offered any resistance as Askern slipped to 71 all out in response to the home side’s 239-6.
League leaders Brodsworth Main maintained their one hundred per cent winning record in Division Two but it was a close run thing against Glasshoughton.
William Drury (58), Alex Snaith (38) and Bradley Maddison (30) helped Main post 183 all out before the visitors replied with 174 all out. Josh Rutherford took 4-29.