The Millers looked on course to take an advantage back to the New York Stadium on Wednesday as they were leading through Joe Newell’s goal until Cameron McGeehan forced home an 88th-minute equaliser.
Warne’s men, whose early lead from Jon Taylor was cancelled out by a Michael Ihikewe own goal in the first half, will return to their own patch as the favourites to progress to Wembley.
“If you’d have given me a draw before the game I would have been happy with that,” said Warne. “I’ll put some smiles back on the faces, a few of them are down so we will pick them up and go again on Monday.
“To come away from here 2-1 up would have been a great result but I can’t be greedy. Scunny played well and they are a great side. So to come here and match them on their own turf is good and we can take credit for that. Hopefully, we can win on Wednesday.
“When I went in it was downbeat like they’d just got beaten. If I’d have offered them 2-2 before the game they would have taken it and if I’d have offered them a one-night only game against Scunthorpe to get to Wembley for the play-off final they would definitely have took it.
“They shouldn’t be downbeat and they gave it their all and you don’t always get what you want.”
The Millers looked like taking a 2-1 win back down the M18 after Newell had scored 58 seconds after coming on as a substitute, firing home with his first touch.
It was the second time they had been in front after Taylor’s opener, which was cancelled out 76 seconds later when Ihiekwe put through his own net.
Scunthorpe caretaker boss Nick Daws has still not been beaten since taking over from Graham Alexander at the end of March and is confident his side can go to South Yorkshire and get a result.
He said: “The play-offs are a different animal but if you have a squad of players that you have belief in then you have a confidence that you can turn it around.
“We have not hidden the fact that playing here up until recent times has been more difficult than it should have been.
“We have been to Wigan, Blackburn and Charlton and got good results so I have every confidence we will go to Rotherham and perform better than we did today.
“I know we can be better, we can pass the ball better. The first part of the first half, was end-to-end, it’s what a play-off should be.
“We attacked with vigour and zest but not consistently enough.
“What I have seen gives me enough confidence we can go to Rotherham and get a result.”