A DOUR defeat to Championship strugglers Birmingham and Solihull provided twice the blow for the Knights as it hampered both the league and cup campaigns.
Due to mounting fixture congestion, the Knights agreed with Birmingham the clash at Damson Park would be a double header for both the Championship and British and Irish Cup.
After the superb performance against London Welsh last week, it was a different Doncaster on show as they folded.
Birmingham fielded three former Knights – player coach Russell Earnshaw, fly half Mark Woodrow and prop Ngalu Tau – who all came back to haunt them.
The Knights conceded an early try to their hosts with winger Simon Hunt touching down and Woodrow converting.
Doncaster hit back with a penalty from fly-half Tristan Roberts after nine minutes but the Bees hit back shortly after with the other winger, Ollie Grove, scoring and Woodrow slotting over a difficult kick to take the scoreline to 14-3.
Flanker Neil Cochrane narrowed the gap with a try on 28 minutes which Roberts converted, and Roberts then chipped away with penalties on 33, 39 and 42 minutes to put Doncaster into an 18-16 lead at the break.
But their lead did not last long and lock Semisi Tualava barged over for a third try which Woodrow improved.
Roberts pulled back a penalty to keep the Knights in touch but Birmingham took full advantage of an inch-perfect grubber kick from Woodrow with Hunt racing through to score his second.
Doncaster pushed for a way back in and had some good possession but failed to do much with it other than add a penalty which gave them a losing bonus point.
The Knights will be hoping for better fortune in the British and Irish Cup this weekend when they travel to Llandovery on Saturday.