Balcan Lighting Supplies Lincolnshire League
Ten-man Market Rasen Town drew with local rivals Horncastle Town at Rase Park (see separate full report).
League leaders Sleaford Town Reserves extended their advantage at the top of the pile, thanks to a Liam Tunstall hat-trick.
The defeat dumped Rustons on to the bottom rung of the league ladder.
Second place remains in the hands of Lincoln Railway AFC, who were held to a 3-3 draw by fifth placed Brigg Town Reserves.
The match of the day at The Causeway between Wyberton and the visiting Skegness Town also finished all square, while champions Hykeham Town made up ground on the chasing pack with victory over CGB Humbertherm.
Meanwhile, Cleethorpes Town Development Squad doubled the gap between them and eighth placed Skegness United with victory at Wainfleet Road.
Results: Hykeham Town 3 CGB Humbertherm 1, Lincoln Railway AFC 3 Brigg Town Reserves 3, Market Rasen Town 1 Horncastle Town 1, Ruston Sports 0 Sleaford Town Reserves 3, Skegness United 0 Cleethorpes Town Development Squad 3, Wyberton 1 Skegness Town 1.