Rovers were two down inside the first four minutes after goals from Jordan Graham and Vadaine Oliver.
But captain Tom Anderson and James Coppinger scored within four minutes themselves to clinch a battling draw.
Doncaster’s winless run stretched to four games, and are now nine points off the promotion pace.
“The first four minutes weren’t ideal and we were climbing a mountain after that,” admitted Butler.
“We spoke a lot about mentality and controlling the controllables, which they did.
“They had a lot of things to deal with – decisions not going their way and the surroundings – but I’m pleased with them.
“It’s a positive point for me. I’m not down about it.”
Rovers got off to the worst possible start when they conceded within 85 seconds. Louis Jones parried Kyle Dempsey’s strike straight into Graham’s path to open the scoring.
And the deficit was doubled soon after when Oliver – the Sheffield-born former York City striker – slammed home his eighth goal in seven games as he volleyed home Ryan Jackson’s throw.
Anderson rose highest to head home Coppinger’s pin-point cross. And Coppinger fired into the bottom corner to restore parity in the 23rd minute. Joe Wright was in the right place at the right time to keep out Alex MacDonald’s effort off the line.
Gillingham: Bonham, Jackson, Cundy, Tucker, Ogilvie, Graham, Dempsey, O’Keefe (McKenzie, 77), MacDonald (O’Connor, 77), Akinde (Lee, 70), Oliver. Unused substitutes: Bastien, Woods, Johnson, Willock.
Doncaster: Jones, Halliday, Wright, Anderson, Horton, Smith, James, Sims (Lokilo, 68), Coppinger (Richards, 61), Okenabirhie (Gomes, 88), Bogle. Unused substitutes: Balcombe, John, Greaves, Robertson.
Referee: W Finnie (Bedfordshire).
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