Sheffield United scored two goals in stoppage time to snatch a dramatic victory and avoid a humbling defeat to League Two side Port Vale.
The Blades made two changes as Vale chief Micky Adams made his first return to Bramall Lane since being sacked as manager last year.
Darryl Westlake replaced right-back Tony McMahon and David McAllister replaced the suspended Neil McDonald in midfield.
Vale’s Jennison Myrie Williams almost sliced into his own net early on and Blades’ Nick Blackman had a shot deflected over but neither side created clear-cut openings in the first half-hour.
Former Millers striker Tom Pope gave Vale a 33rd-minute lead after a blunder by Harry Maguire and ran over to celebrate his 21st goal of the season with Adams.
Neil Collins was sick before the second half began and was replaced by Marcus Williams.
Miller’s header brought a reflex save from Chris Neal as the Blades searched for the equaliser.
Neil Beak blocked from Blackman and sub John Vogue mis-kicked in the area before Miller’s downward header bounced over the bar.
The Blades finally equalised in the 90th minute when Miller glanced home a cross from Flynn.
Then in a dramatic finish Miller tucked home the winner after Flynn’s shot had been parried in the fourth minute of stoppage time.