Queens clinched the Second Division title in emphatic style with a thumping win away to the only team that could have caught them.
Nicky Clark and Michael Paton each scored twice in the first half to quickly erase any faint hopes Brechin had of reeling in the runaway leaders.
The visitors also benefitted from a Ewen Moyes own goal and Gavin Reilly found the net after the interval.
The hosts' evening got worse when Gerard McLauchlan was sent off.
Queen of the South have lost just one league match all season and can start the promotion party with six fixtures to spare.
Allan Johnston's side turned in a fantastic first-half display to halt an 11-match unbeaten run from Brechin.
The visitors needed just 18 seconds to break the deadlock as top-scorer Nicky Clark fired into the top corner from 12 yards, before Paton doubled his side's advantage with an 18-yard strike two minutes later.
Moyes then diverted Christopher Mitchell's cross into his own net from 12 yards.
Paton netted his second from 20 yards and Clark capped off a dominant 45 minutes by taking his tally to 33 for the season with a close-range finish three minutes before the interval.
Shortly after hitting the post, Reilly got his name on the score-sheet from six yards.
A stunned Brechin, playing at Forfar's Station Park due to the drainage problems at Glebe Park, were reduced to 10 men with 14 minutes remaining when McLauchlan was shown a second yellow card for a bad challenge on Clark.
A fantastic display by Queens who are worthy champions and delighted the 400 travelling support.
Brechin: Andrews, McLauchlan, Hay, Moyes (Pursehouse 55), Paul McLean, Trouten, Brady, Fusco, McKenna (Jonathan Stewart 58), Jackson, Carcary (Ryan Stewart 71). Subs Not Used: Nelson, Murdoch.
Sent Off: McLauchlan (76). Booked: Trouten, McLauchlan, Pursehouse.
Queen of the South: Robinson, Mitchell, Durnan (McGuffie 58), Higgins, Holt, Burns, McKenna, Paton, Carmichael (Gibson 66), Reilly, Clark (Lyle 78). Subs Not Used: Atkinson, Young.
Goals: Clark 1, Paton 3,Moyes 18 og, Paton 36, Clark 42, Reilly 57. Booked: McKenna
Ref: Barry Cook