Ross Lafayette’s brace looked sufficient to see Welling United to victory before Staines came back to claim a share of the points.
Welling made five changes to the team who lost at Salisbury, some enforced, and looked to have done enough until the late Staines comeback.
Lafayette had come closest to breaking the deadlock for Welling when his powerful drive came back off goalkeeper Jack Turner’s legs before he put Welling ahead with a firm header from Joe Healy’s sumptuous cross five minutes before the break.
Wings’ leading scorer repeated the trick five minutes after the interval when Jamie Day’s free kick was met by a towering header from Ben Martin that Lafayette guided home with his head.
Barney Williams went down badly and was carried off on a stretcher with Jake Gallagher, who had been unfit to start, having to fill in at left back.
Kiernan Hughes-Mason replaced the hard working Theo Fairweather-Johnson as Welling hoped to use his pace to breach the Swans’ defence for a third time.
Kurtis Guthrie had a goal disallowed and came close twice more before Staines stunned Welling with eleven minutes remaining.
David Wheeler broke in from the right wing and Dan Brown netted from close range.
Referee Ryan Atkin failed to award Welling a spot-kick for a blatant body check on Lee Clarke and Staines made the most of their let off by levelling through substitute Louis-Rae Beadle.
Wheeler then struck a pile-driver against the post as Welling struggled to clear their lines before Assistant Manager Barry Ashby was sent off for voicing his opinion of the referee too forcibly.
Although disappointed to drop the point, second placed Salisbury City were held by Dover Athletic meaning that the Wings require just four points from their remaining three games to guarantee the Blue Square Bet South Championship and promotion.
Salisbury City: Turner, Mills (Taylor 59), J. Brown (Worsfold 59), Ferrell, Page, Ifil, Wheeler, Ferguson, Marsh (Beadle 59), D.Brown, Lodge.
Unused substitutes: Frear, Lewis, R. Sinclair.
Welling United: Turner, Franks, Williams (Gallagher 68), Day, Martin, Acheampong, Fairweather-Johnson (Hughes-Mason 71), Clarke, Guthrie (Reid 90), Lafayette, Healy.
Unused substitutes: Mott, Kinch.
Referee: R. Atkin
Attendance: 356
Welling star player: Ross Lafayette.