The Tigers appeared to have the game – and their top-flight status – wrapped up as they rushed into a 14-4 lead with tries from Luke Dyer and Danny Sculthorpe and three goals from the boot of Danny Brough.
Tigers boss Terry Matterson praised the hard work put in by his players but admitted that they had not been able to convert chances into points.
"The effort from the players was outstanding. We prepared well and we had chances but we just could not take them” he said..
"The players are shattered because of the effort they put in but they will be all right against Wakefield."
Salford coach Karl Harrison said that the Reds needed to hear some harsh words at the interval, adding that they would have to improve if they wanted to make any impact on the play-offs.
"At half-time the players got an old-fashioned rollicking and in the second half I thought we dominated the game” he said.
"We've never been in the play-offs before but with this group of players I'd like to think we can compete. We probably need to be a bit smarter come the play-offs."
A bad night was made worse for the Tigers when Wakefield beat Bradford; Castleford must now travel to Belle Vue next weekend in the knowledge that a defeat will see them relegated.