Douglas Athletic were thrashed 4-1 at Malew to lose their spot at the top of the table.
Andy Glover, Kraig Marsh, Dean Kinley and Craig Howard netted the goals for the fast improving southerners whose place at the summit has now been taken by Marown.
They saw off lowly Douglas & District 7-2 at Crosby.
Ashley Heginbotham (two), Sean Shimmin (two), Niall Quayle, Joey Rothwell and Stuart Morris grabbed the goals.
Marksman Daniel Clague-Stewart and Ben Skelton replied for D&D.
With third placed Ramsey Youth Centre not in action. Colby missed the chance to move up the table after Castletown shocked them in the southern derby.
Paddy Cooper and Joel Callow were the scorers for seventh placed Town in a 2-1 win.
Jamie Heeney scored for the hosts.
Douglas Royal would have kept alive their faint promotion hopes if they had taken advantage but lost at home to Braddan – Kyle Sum-Warrander with the only goal of the game in the second half.
A last minute winner from Craig Cowin ensured Pulrose United edged out Foxdale in a seven goal thriller at Billy Goat Park – Dave Priestnal, Barry English and David Skillen grabbed the others for the visitors.
Onchan were 5-1 home winners over bottom club Governor’s Athletic – Ryan Gartland (three), Luke Price and Rob Byrne the scorers.
Ross Engwin notched the Athletic consolation.