Oldham had Everton reeling when Jordan Obita gave them a 13th-minute lead. Goals from Victor Anichebe and Phil Jagielka either side of half-time put David Moyes' men in the driving seat but Everton goalkeeper Tim Howard was forced to save well from Smith and Robbie Simpson.
Smith produced an all-action display to score twice in Latics' round four triumph over Liverpool and the 23-year-old climbed off the bench to head home Jonathan Grounds' corner in the fourth and final frantic minute of stoppage time.
Nikica Jelavic had a glimmer of an opening in the eighth minute from Steven Pienaar's through ball but the Croatia striker was crowded out. Jose Baxter then pulled back the advancing Pienaar to present Leighton Baines with an inviting free-kick opportunity.
The England left-back's strike was deflected over and, after Oldham dealt with the resulting set-piece pressure, Boundary Park was sent into raptures. Lee Croft broke unchallenged from his own half down the Everton left before driving low across goal where Obita's perfectly-timed run was rewarded with a tap-in.
The lead remained intact for 11 minutes until Jagielka's raking long ball was flicked on by Jelavic and Anichebe got the better of Jean-Yves Mvoto to rifle past Bouzanis. Undeterred, Oldham surged forward in response and Obita thudded a shot against the base of the post.
In the 32nd minute, Jelavic came out on the wrong side of a marginal offside call when he converted Pienaar's defence-splitting pass. Mirallas replaced hamstring victim Anichebe and the new man would make an instant impact in the 48th minute, an in-swinging corner from the left caught out Dean Bouzanis, allowing Jagielka to nod into an unguarded net.
Another Mirallas corner had Oldham in trouble before the hour, arching past the massed ranks at the near post and narrowly evading Leon Osman. Philliskirk responded by sending on Oldham's fourth round hero Smith for Chris Iwelumo and club captain Dean Furman in place of James Wesolowski.
Jelavic passed up the opportunity to make the tie safe with eight minutes to play, blazing over from Darron Gibson's fine flighted pass. In the 89th minute Simpson had a glorious chance to earn a replay as he shrugged off the attentions of Phil Neville to collect James Tarkowski's lofted pass.
But Howard stopped a shot that lacked purchase before seeing the rebound lashed into the side netting. Much to Simpson's relief and the locals' delight, Smith would sensationally spare his blushes.
- Sports & Recreation
- Phil Jagielka
- Jordan Obita
- Steven Pienaar
- Victor Anichebe
- Robbie Simpson