St Mary’s dispatched Dunnington thanks to goals from Damon Cox, Richard Dunning and Dean Nuttall.
Olly Newby replied for Dunnington, whose defeat saw any hopes of retaining their title all but disappear.
Malton are now five points clear of Riccall, with the second-placed side having two games in hand.
Riccall were thrashed 7-2 by third- placed Huntington Rovers on Saturday.
Huntington took the lead after 13 minutes when Chris Dyson hit a powerful left-footed drive past the ’keeper and Jon James doubled their advantage with a header soon after.
James added his second just before the break, and a Gary Newton penalty extended the lead shortly after half-time.
Dyson fired a fifth for Huntington shortly before Lee Jackson scrambled home their sixth.
Riccall then had a mini-revival with Mike Braithwaite hitting a quick-fire double, but substitute Lee Bunce had the final word with Huntington’s seventh in the last minute.
Karl Barbaro put the visitors ahead with a neat finish on 27 minutes only for Lee Stewart to equalise five minutes before half-time.
Stewart showed his class with a second half hat-trick that extended Hoppers’ unbeaten run to 14 games.
York St John kept their survival hopes alive with a second successive victory – a 6-4 win at York RI.
Michael Grugan put the visitors in front after 11 seconds and doubled the advantage minutes later. Tom Ryan added a third goal for the away side from the penalty spot but strikes from Ben Jones, Liam Keenaghan and Lee Powell ensured the sides were level at half-time.
Nick Hartley hit RI’s fourth in the second period but it proved to be in vain as Lee Winslow, Tom Shepherd and James Peavoy won it for the students.
Johnny Brown and Tom Paley gave Terrington Glory a two-goal lead at home to St Clement’s, and Alan Goforth rounded off a 3-0 win.
Tadcaster Magnets triumphed 3-1 at Tockwith to secure the division one title. Adam Field (2) and Sam Harrision scored the visitors’ goals, with Stephen Gay replying.
Osbaldwick and Church Fenton both won to continue the scrap for the second promotion place.
Osbaldwick took the lead at Hamilton Panthers after 13 minutes through Michael Whiteley, only for Zac Lovely to level. Nick Lawrie restored the away side’s lead and then it was one-way traffic with Tom Wheatland adding a third and Lawrie completing the scoring.
Church Fenton beat Total Sports United 9-0.
Brooklyn routed Pocklington 8-0 with two goals apiece from Andrew Metcalfe, Michael Brown, Andrew Philips and David Thompson.