Yasir is the last hope for Pakistan to have a sniff at the victory provided that he doesn't succumb to the pressure of the role required of him at the other end. If he nicks one to the keeper ('cause he's vulnerable to deliveries outside off stump and can't help but poke at them) then that'll be curtains for Pakistan 'cause I have no trust whatsoever in Rahat to hold one end.
My lack of faith in Rahat's batting expertise is predominantly driven by the fact that the protagonist can't hold the bat properly to save his life let alone defend a couple of deliveries at the end of over to give the strike back to Shafiq. Yes flukes happen as mentioned in the OP, anyone can have an odd day with the bat even the most incompetent ones but it shouldn't be made into something to judge a player's ability or expect them to pull off the unthinkable. Most likely he'll perish in pursuit of defending final two deliveries or run himself out before rotating the strike.
On the contrary, even if he had once in a blue moon outing with the bat and somehow contributes to taking Pakistan close to the victory, most likely he or his partner will throw it away due to the pressure of the historic occasion. The more closer they get to the target, the more nerves will start to kick in disrupting their natural flow making them prone to commit mistakes.
Either way it should be an interesting first session tomorrow, not that it matters but I'd love to see the margin of defeat less than 50 runs, if these two can take the game forward to that point, it'll be job well done and it'll also help salvage some of the pride besmirched due to our embarrassing batting in first innings. Fingers crossed!