The 2015-16 Championship play-off final will be between the teams who occupied the top two places in the table at the end of the regular season.
Bristol, who finished in top spot for the third season in succession, were never in danger of losing out against Bedford following their resounding win in their away leg.
Doncaster Knights, on the other hand, still had it all to do in the return against Yorkshire Carnegie at Castle Park despite taking a 13-point lead into the biggest home game in their history.
The importance of that cushion was underlined as Carnegie came from behind to win the second leg 17-14 in front of the biggest ever crowd for a club game at Castle Park.
Knights will have to play better with the ball than they did against Carnegie, who produced an improved performance in the second-leg, to beat Bristol in the final.
But having won at Ashton Gate and going close in the return, it’s all to play for.
Carnegie were the first to threaten with full-back Joel Hodgson joining the line to good effect, but it was Knights who put the first points on the board.
Fly-half Declan Cusack found the target from 43 metres out to increase Knights overall lead to 16 points.
Wing Andy Bulumakau, a scorer at Headingley, was bundled into touch just short of the line from a move instigated by scrum-half Michael Heaney.
Full-back Paul Jarvis showed he is now back to his best after his foot injury, when jinking past several defenders before losing the ball just outside the Carnegie 22 after getting on the end of a risky pass by Bulumakau.
Carnegie threatened again through impressive centre Peter Lucock on 15 minutes.
Knights suffered a double blow two minutes later when Carnegie were awarded a penalty try, which rugby league legend Kevin Sinfield converted, and had leading try-scorer Latu Makaafi sin-binned.
Fortunately Knights didn’t pay a further price, and actually closed the gap to 7-6 with a second Cusack penalty while they were short-handed. But it needed good defence by Heaney and No 8 Alex Shaw to stop danger man Ryan Burrows in full-flight.
Cusack edged Knights into a 9-7 lead from a penalty which also saw propo Charlie Beech sin-binned and the home side rode their luck when a stoppage-time penalty by Sinfield came back off the near post.
The second half got off to a sensational start with strong-running centre Will Hurrell breaking the line just outside the Carnegie 22 and charging over for an unconverted 42nd minute try which left the Leeds club trailing by 20 points.
Replacement Andy Saull threw his side a lifeline when touching down from a driving maul on 57 minutes but Sinfield, who will have hoped to have bowed out of the game on a better note, again missed the conversion leaving his side 15 points adrift over the two legs.
Cusack was also wide with a long-range effort on 66 minutes.
Knights had to dig deep in the last ten minutes or so and Carnegie’s pressure eventually paid off on 79 minutes when wing Jonah Holmes, who had earlier made a couple of strong breaks, touched down out wide from a Sinfield kick to set up a tense finish.
Doncaster Knights: Jarvis. Bulumakau, Clark, Hurrell, Lewis; Cusack, Heaney; List, Hunter,Quigley, Challoner, Phelan, Makaafi, Hills, Shaw. Rep: Veikoso, Brugnara, Sprotson, Stedman Young, Bryant, Field.
Yorkshire Carnegie: Hodgson, Holmes, Forysth, Lucock, Prell; Sinfield, Pilgrim; Beech, J Walker, Tideswell, Schofield, Smith, Beck, C Waker, Burrows. Rep: Nilsen, Imiolek, O’Donnell, Ryder, Saull, Green, Stegman.
Referee: Ian Tempest (RFU)