Knights welcome former winners Munster A to Castle Park on Saturday (2pm) - the first time they have ever faced Irish opponents in the cross border competition.
And they will be hoping to maintain their strong cup form as the club go in search of a much-needed pick-me-up.
Chief executive David Ryall this week refuted any suggestion that Clive Griffiths’ job may be under threat after an eight-game losing run in the league.
Knights are without a league win since September and last Saturday’s home defeat to Jersey - which director of rugby Griffiths had labelled as a “must-win” game - piled more pressure on the Welshman and his players.
However, Knights have backed their boss and insisted it was business as usual at Castle Park.
“I’ve been with Clive this morning and it’s no different to last Monday,” Ryall said earlier this week.
“There’s no issue with Clive Griffiths.
“The status quo has not changed.
“We are not where we would have liked to have been, ideally, but we’re only halfway through the season.
“There’s no panic. We don’t panic at this club.”
Knights are currently 11th in the Championship, one place and eight points above bottom club Plymouth Albion.
Welshman Griffiths, who failed to save the club from the drop two years ago but then oversaw an immediate return to the Championship last season, is in his second spell at Knights.
He signed a new contract last year to remain in charge until 2016.
Doncaster’s cup form has been in stark contract to their performance in the league, qualifying for the quarter-finals as top seeds after taking 29 points from a possible 30 in the pool stages.
Knights’ only previous semi-final appearance came in the inaugural season of the B&I Cup in 2009/10.
Season ticket holders and under 16s are admitted free on Saturday. Adult tickets are priced at £5.