Hearts end home slide
Danny Grainger's long-range strike earned Hearts their first Clydesdale Bank Premier League victory at Tynecastle since the opening day of the season.
The left-back powered the ball into the top corner amid some early pressure and the home side repelled Motherwell's comeback attempts to end the SPL's only unbeaten away record.
Motherwell had some good possession and midfielder Nicky Law had a header cleared off the line but Hearts were never under the cosh and substitute John Sutton squandered a chance to make the game safe.
Matters only grew worse for Motherwell when centre-back Shaun Hutchinson had to come off at halftime with what appeared to be a hamstring injury.
Murray Davidson's scrappy first-half opener was enough to earn the McDiarmid Park outfit another three points in a sequence that was sparked by an unlikely victory over champions Celtic in mid-September.
The win should have been more comfortable and would have been had Nigel Hasselbaink not failed to find an open net in a second half in which Kilmarnock could not spark a comeback.
With just a minute remaining, Hasselbaink - who had passed up another one on one with Cammy Bell - finally scored the second the Perth men deserved.
And, with the game now beyond them, Killie netted what proved to be no more than a consolation in injury-time courtesy of James Fowler's deflected strike.
McMenamin came off the bench and made a big impact by grabbing what proved to be the winner with seven minutes to spare.
In an entertaining match Leigh Griffiths gave Hibs the lead in the sixth minute but Stuart Kettlewell levelled three minutes later.
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Iain Vigurs then gave County the lead in the 34th minute before Hibs equalised through James McPake on the stroke of half-time.
The match looked to be heading for a draw in a equally entertaining second half but super sub McMenamin popped up with the winner.
John Rankin's 22nd-minute goal was cancelled out eight minutes into the second half by Aberdeen striker McGinn, who netted in Northern Ireland's midweek draw in Portugal on the occasion of Cristiano Ronaldo's 100th cap.
After 88 minutes, United should have sealed victory but Rankin fired wide across goal with a wasteful ball when he should have shot himself or passed to Johnny Russell.
McKay put Caley Thistle in front after four minutes and Gary Warren doubled the lead two minutes later as the visitors appeared set to extend their unbeaten run to six at Dens Park.
Colin Nish pulled a goal back after 13 minutes, but Andrew Shinnie converted an 81st-minute penalty before laying on McKay's second as Terry Butcher's men climbed to third place in the standings.
The hosts have now lost five successive games to sit four points adrift in an otherwise tight SPL table.