With the game in its 87th minute, the Whites were staring down the barrel of another frustrating matchday made all the more frustrating because title rivals West Bromwich Albion and Swansea City were both trailing at that stage.
At Deepdale, Leeds were reeling from the sucker punch of a counter-attack goal by Tom Barkhuizen when on-loan striker Nketiah entered the fray and did what Bamford and his team-mates had been unable to by finding the net.
The England Under-21 international’s looping header came late enough to feel like a winner, but in fact clinched a 1-1 draw,
Until then it had been a familiarly exasperating story from the Whites.
Not for the first time, they bossed their opponents without putting them to bed. Bamford was the chief culprit, but by no means the only one.
The centre-forward has not scored in eight games and until he does, the debate over whether Nketiah should make his first Championship start will go on, no matter how much his rival brings in the build-up.
Bamford had three chances in a scoreless first half and was unable to convert any of them. The first was very difficult, twisting and stretching to get his head on the first of seven corners for the visitors in the opening 45 minutes, but unable to hit the target.
He ought to have from his next two opportunities, blazing his eighth-minute effort after Helder Costa caused problems by drifting in from the right. After 21 minutes he headed over from a Kalvin Phillips corner.
There ought to have been a fourth chance but when Jack Harrison played a lovely pass to Stuart Dallas, Ben Davies’s excellent tackle beat Bamford to the loose ball from Declan Rudd’s save.
Egzan Alioski, again at left-back in an unchanged side, shot just wide when Harrison nodded a right-wing cross into his path and when Bamford was just unable to stretch to Dallas’s centre, it summed up his half.
When Mateusz Klich pulled the ball back from the byline after 68 minutes, Bamford opened his body up too much and screwed his shot wide. The travelling fans, who had just watched him set-up Dallas’s deflected shot with the hold-up play which is keeping him in Marcelo Bielsa’s side, chanted his name in solidarity, but as soon as Preston took the lead, Nketiah was unsurprisingly summoned from the bench to replace, not partner, Bamford.
Not that Bamford was the only guilty party as Leeds took control of a game which Preston had shaded in the opening quarter. Klich had a shot blocked and while Leeds’s deep 33rd-minute corner looked well-rehearsed, Costa volleying over was not part of the plan. When another clever flag kick followed early in the second half, Alioski saw his first shot blocked and put his second wide as Dallas over-ran a pulled-back corner.
With the chance to overtake their hosts in the table, Alex Neil’s Preston started the better, Daniel Johnson off balance and off target, Kiko Casilla forced off his line by an unhelpful Gaetano Berardi backpass, Luke Ayling having to deal with a dangerously curled Alan Browne free-kick, while Ben White dealt with a David Nugent flick-on. But as the half went on, Leeds took a firm grip on it, enjoying 60 per cent of possession.
The interval did not disrupt Leeds’s flow, though in a sign of things to come, Barkhuizen almost punished them on the counter-attack after 55 minutes, rolling the ball along the six-yard box only to find that the Preston players had been no more able to keep pace with him than Leeds.
Harrison responded by steering a low volley into the side-netting, but it was Preston’s chance which was a sign of things to come.
Another well-crafted Leeds move saw Klich lay the ball into Alioski’s path but Darnell Fisher’s block proved even better than it first appeared when Sean Maguire broke down the left and laid on a tap-in for Barkhuizen.
The next time Maguire broke down the right, with seven minutes left, his shot from a tight angle forced a corner Barkhuizen headed over.
It was starting to look like one of those nights but Nketiah had other ideas, drawing a foul and a booking from Fisher, then looping his header in when the ball was played back in after the original set-piece was blocked.
Relieved though they were, Leeds were not yet home and hosed, Brad Potts flicking a header just wide.
Preston: Rudd; Fisher, Bauer, Davies, Rafferty; Pearson, Johnson; Potts, Browne, Barkhuizen (Green 90+1); Nugent (Maguire 71). Unused substitutes: Ripley, Gallagher, Hughes, Ledson, Stockley.
Leeds: Casilla; Ayling, White, Berardi (Roberts 78)i, Alioski; Dallas; Costa, Phillips, Klich, Harrison; Bamford (Nketiah 78). Unused substitutes: Miazek, Douglas, Gotts, Davis, Clarke.
Referee: K Friend (Leicester).