The Knights were unfortunate not to earn a losing bonus point and were prevented from doing so by a late penalty from Bedford fly-half Will Maisey.
Doncaster started promisingly as flanker John Kelly and winger Jack Spittle threatened, but it was Welsh winger Kyle Evans who almost scored after seven minutes following a burst by back row forward and captain Sam Graham.
However, Evans was tackled into touch a few metres from Bedford’s line.
Despite this aggressive opening, Bedford opened the scoring in a close contest with two penalties from fly half Will Maisey, punishing Doncaster’s mistakes.
But the Blues’ 6-0 lead was cut to 6-3 when the accurate goal kicking of fly half Sam Olver put over a penalty.
The pack drove to Bedford’s line and after several raids, prop Gaz Denman smashed his way over, and with Olver converting, Doncaster seized a 10-6 lead.
Bedford fought back through winger Pat Topley who grabbed the ball after hesitant defending, but Doncaster’s pack then created pressure on Bedford’s line resulting in scrum-half Alex Dolly shooting over for the teams’ second try. Olver’s second conversion stretched the lead.
The second half began badly for Doncaster as Bedford’s attack set up a thrilling try for full back Rich Lane. Maisey’s conversion now put Bedford one point ahead at 18-17.
The Midlanders maintained the pressure and with more ball won a line-out which created a third try-this time for replacement forward Tui Uru, and with Maisey converting again, Doncaster fell further behind at 25-17. The Knights, though, are resilient and reduced the gap to 25-20 once Olver’s penalty went over. Olver struck again with another penalty-slashing Bedford’s advantage to only 25-23.
But Doncaster’s chances disappeared as Maisey put over two penalties.