Championship: Doncaster Knights 24-20 Jersey Reds
Jersey's Championship play-off hopes are over after a narrow loss to Doncaster Knights, who secured their own top-four spot with the win.
Wingers Tyson Lewis and Dougie Flockhart went over to help the hosts to a crucial victory at Castle Park.
A penalty try and late touchdown from Jake Armstrong were only enough for a losing bonus point for the Reds.
It leaves them with too much to do in the final league game against Richmond next weekend.
The Reds went into the match on the back of a 10-game winning-streak, knowing an 11th consecutive victory would give them a great chance of making it to the play-offs with a home match against Richmond on the final weekend of the regular season to come.
Doncaster, who started the day two points and one place above their opponents, were 13-3 ahead early on thanks to Flockhart's penalties and a converted try from winger Lewis, who ran through from his own half to score.
Callum Sheedy's kicking kept the Reds in touch before a penalty try, awarded after Rich List's infringement at the maul, pulled the visitors level.
A penalty edged the Knights three points in front again despite List's spell in the sin-bin, before Sheedy missed penalties either side of half-time.
Flockhart darted in for his fifth try of the season and added a further penalty to secure the win for the Knights, despite Armstrong's converted try from a quickly-taken penalty with the final move.
The result, coupled with Cornish Pirates' loss to Richmond, means the Knights can now look forward to the play-offs while Jersey will prepare for the British and Irish Cup final and will try to claim their highest-ever league finish.
Reds head coach Harvey Bijon told BBC Radio Jersey:
"There's no doubt that ill-discipline and unforced errors cost us at crucial times.
"We just gave Doncaster easy outs and when we did have opportunities to take points we just forced things.
"I'm pretty proud of the way the players have fronted up, let's enjoy next weekend and look forward to our British and Irish Cup final."
Doncaster: Jarvis; Flockhart, Bulumakau, Hayes, Lewis; Humberstone, Heaney; List, Hunter, Quigley, Challinor, Young, Ram, Hills (capt), Shaw.
Replacements: Bergmanas, Nelson, Sproston, Williams, Carpenter, Edgerley, Cusack.
Jersey: Cuthbert; Watkins, Davies, Ma'afu, Scott; Sheedy, Hardy; Woolmore, Buckle, Kerrod, Phillips, McKern, Freeman (capt), Graham, Haining.
Replacements: Selway, McCarthy, Armstrong, Kolo'ofa'i, Argyle, Dudley, Cope.
For the latest rugby union news follow @bbcrugbyunion on Twitter.