Doncaster completed a Championship double with a cliff-hanger 36-34 win over lowly Swinton Lions at the Keepmoat Stadium.
But their performance fell well below that of a week earlier when they became the first side to beat leaders Leigh.
Paul Cooke’s side were hanging on at the death after looking to be coasting to victory when leading 30-6 early in the second half.
Swinton’s revival was all the more remarkable given that they played most of the second half with only 12 men.
Doncaster’s inability to defend the high ball contributed to their failure kill-off the wounded Lions.
The third-bottom Lions drew first blood, veteran centre Mick Nanyn, who also added the extras, crossing from close range on 13 minutes.
The visitors threatened again before Dons winger Nev Morrison intercepted a pass and raced 90 metres to score in the corner on 16 minutes.
Stu Sanderson, resuming the kicking duties in the absence of Dave Scott, added the touchline conversion to level the scores.
The Dons edged into a 12-6 25th minute lead when prop Mark Castle celebrated his return to action following a lay-off with a back problem by off-loading the ball in the tackle to send full-back Tom Hodson over from close range near enough for Sanderson to again convert.
Hooker Kyle Kesik scored a typical close-range try two minutes later, which Sanderson converted to earn the Dons a slightly flattering 18-6 lead.
But for a kinder bounce, record try-scorer Lee Waterman would have scored after he had hacked a loose ball on.
Waterman was not to be denied, however, and he scored out wide just before the break – Sanderson again tagging on the extras – shortly after.
Swinton forward Zach Johnson was sent-off, and team-mate Josh Barlow sin-binned along with Waterman, following a 42nd minute flare-up.
Doncaster wasted little time in cashing in on their numerical advantage, half-back Richard Wilkinson capitalising on good work by the industrious Craig Robinson.
Wilkinson struck again after latching on to a loose ball and kicking ahead after Swinton second-rower Danny Bridge had powered his way over.
The Lions bombed a certain try with a wayward pass before hooker Andy Ackers went over on 68 minutes.
When James Brown (73) and Ed Barber (77) crossed for late tries as the Dons visibly wilted,