Jamie Harris struck twice to kill off Oakhill’s faint title hopes and leave Haroldeans with one hand on the MJSL league trophy.
Ivan Gee’s men are now nine points clear of the Lions with eight games remaining as they inflicted a second defeat of the season in the Manchester students.
The prolific Bobby Abrams was also on target, while Cabral Christian rounded off an emphatic 4-0 victory for the Merseysiders.
Hyde Park Rovers missed out on the chance to move level on points with Oakhill after suffering a 2-1 home defeat by Manchester Maccabi 3rd.
Two goals from Jake Kelly gave the reigning champions all three points with David Herman scoring for Rovers.
In the Shonn Trophy, Crumpsall pulled off a stunning five star show to defeat South Manchester Sports Club 2nd 5-2.
Daniel Rose scored twice for the visitors, while Michael Freedman, Benjy Silverman and Ben Kayser also got in on the act.
Aden Levin and Dan Linton replied for South as they slumped to a shock home defeat.
Crumpsall will face Republic of Mancunia 1st or Broughton in the quarter-finals.