Doncaster had to settle for a losing bonus point as Leigh Centurions completed a Championship double at a sun-drenched Keepmoat Stadium.
The Northern Rail Cup finalists led throughout in their six-point win, but they had to work much harder than they had done when beating the Dons 34-8 at home earlier in the season.
The Dons trailed by 18 points early in the second half, but finished the stronger side in a game played in energy-sapping heat, and were left ruing earlier chances as they scored two late tries before running out of time in a 36-30 defeat.
The Dons lacked influential play-maker Paul Cooke, but utility back Liam Kay scored two tries in addition to setting up another, filling in at stand-off.
“Liam had his best game of the season and I thought he was head and shoulders above everyone else and has given me food for thought,” said Dons boss Tony Miller, who expects to have Cooke available for the visit of Hunslet on Sunday.
“Having said that, I thought we missed Paul and we lacked a bit of composure at times – especially in the first half.
Miller, who will be checking on prop Matt Carbutt (elbow) today, still entertains hopes of a play-off spot whilst still looking over his shoulder at the relegation battle.
“I think the next four games , three of which are at home, will probably determine whether we will be challenging for a top-eight spot. The Hunslet game is certainly one we need to win.”