Of course it was Michael Smith, with his 25th goal of a season which saw him sweep the board at the Millers' end-of-season awards do on the Thursday, who got the goal they had spent the whole second half pushing hard for and wondering if it would ever come.
The hugs and cheers in the stands and on the pitch at full-time spelt it out: this was a huge three points for the Millers.
Manager Paul Warne looked cucumber cool with the ball tucked under his arm as he waited for Wes Harding to trot over and launch a long throw-in but having seen Mikel Miller go off injured, goalkeeper Viktor Johansson treated twice and Michael Ihiekwe flat out on the turf for a lengthy period of time, goodness only knows what was going on inside.
The last half-hour in particular had bee bursting with nearly moments in front of the Ipswich Town goal but James Norwood had missed a real sitter in the first 10 minutes, and Johansson had been forced into a good save in between his injury scares.
When Ben Wiles's shot was blocked from the throw-in, it looked like another addition needed to be made to the catalogue of nearly moments but Smith calmly swept home the loose ball for what proved to be the only goal of a hard-fought and badly needed victory for the Millers.
It took them back into the top two ahead of Milton Keynes Dons match at home to Sheffield Wednesday, the final part of Sky Sports' Saturday League One trilogy. If that puts a bit of pressure on the Dons, it was far from a stroll in the park for Rotherham.
The referee must have taken some sadistic pleasure in it, adding nine minutes of stoppage time. It was correct, but still cruel.
Nobody in the 9,364 crowd needed telling how important the game was, judging by the racket they made as the players came out of the tunnel to kick off.
The volume went up another notch when the Millers won a second-minute corner but Wes Harding's shot from a Michael Smith flick-on was blocked and Chiedozie Ogbene shot wide.
With Jordi Osei-Tutu back after what Rotherham were worrying days earlier might have been a broken foot, winger Ogbene was at centre-forward in a reshuffled pack, with Huddersfield Town loanee Rarmani Edmonds-Green reintroduced to the back three and Dan Barlaser dropped to the bench as manager Paul Warne just searched for something different from a team who had won just two of their last nine games in all competitions, and lost their previous three league matches to leave an automatic promotion that had been starting to look a formality in some doubt.
For all that Rotherham came flying out of the blocks, Michael Ihiekwe heading wide at a deep Osei-Tutu free-kick, they needed a huge let-off in the eighth minute, James Norwood fluffing an exceptional chance laid on by Wes Burns when the wing-back got to the byline.
Michael Smith and Ben Wiles, playing in the hole behind the front two, both hit the ball out of play attempting over-ambitious switches and as the crowd took a collective breath, the 1,087 travelling Ipswich fans filled the void.
When Mikel Miller went down injured in the 21st minute, both teams took a time-out in weather so warm assistant manager Richie Barker's obligatory shorts no longer looked out of place. Barker handed out tactical instructions and Warne was forced to reshape his side, Barlaser's introduction pushing Ogbene back out wide as the side went from 3-4-1-2 to 3-1-4-1-1.
The crowd were able to pick their intensity back up as Barlaser stood over a 29th-minute free-kick but Wiles volleyed it into a crowd of players for a corner that come to nothing.
Ollie Rathbone, looking more like himself after some tired recent performances, won the ball high in the 34th minute, played a one-two with Smith and saw his shot blocked by Elkan Baggott, the 19-year-old centre-back with over 1m Instagram followers who was making history as the first Indonesian to play in the Football League.
The chance, though, came only a minute after a cross from left wing-back Dominic Thompson had somehow bobbled right across the Rotherham area.
Bersant Celina showed irritating Rathbone's energy was proving to Ipswich when he reacted to a foul by shoving him over. A booking for daftness rather than a red card for malice was probably the right decision by Peter Wright but it would certainly have been different had it been put to a public vote.
Rotherham took control after half-time but it was littered with what-ifs and injury scares.
Ogbene could not quite jump high enough to get the contact he needed on an Osei-Tutu cross in the 54th minute and when Rarmani Edmonds-Green put the ball back in, Smith's dive was an inch or two short.
The talisman was only able to get a faint touch on Barlaser's deep free-kick and Rathbone sank to his knees when Ogbene was just unable to stretch to what would have been a wonderful through-ball.
Ihiekwe lay prone on the turf for a worryingly long time after a clash with Norwood at the start of the half but was able to carry on.
The injury Warne fears the most, though, is to Viktor Johansson with Josh Vickers' season ended by injury and third-choice goalkeeper Joe Chapman yet to play senior football.
So of course after 65 minutes Sone Aluko's boot caught Johansson as both went after a loose ball. Aluko had to be substituted, only after a yellow card, but fortunately the goalkeeper was able to continue after lengthy treatment.
He made an important save in the 72nd minute after centre-back Luke Woolfenden rampaged into Rotherham's area and Burns pounced onto Wes Harding's clearance.
A couple of minutes later he was sat down on the turf as his team-mates draped themselves in wet towels, but he carried on.
If that was a relief, it was nothing compared to the goal.
Smith could have wrapped things up in stoppage time but floated a shot past the far corner and headed over a Wiles cross.
Well, it was never going to be straight-forward, was it?
Rotherham United: Johansson; Harding, Ihiekwe, Edmonds-Green; Osei-Tutu (Wood 90), Rathbone, Lindsay, Miller (Barlaser 23); Wiles; Ogbene, Smith.
Unused substitutes: Chapman, Mattock, Ferguson, Ladapo, Kayode.
Ipswich Town: Walton; Donacien, Woolfenden, Baggott; Burns, Bakinson, Morsy, Celina (Pigott 79), Thompson; Aluko (Chaplin 66), Norwood (Bonne 66).
Unused substitutes: Penney, El Mizouni, Carroll, Hladky.
Referee: P Wright (Merseyside).