Hull KR (18) 28
Tries: Charnley 3, Briscoe Goals: Dobson 6
Castleford (12) 26
Tries: Ferres, Arundel, Chase, JonesGoals: Westerman 5,
Dobson scored six kicks for Hull Kingston Rovers
A long-range penalty from Michael Dobson gave Hull KR a last-second victory against Castleford.
A see-saw game saw Josh Charnley grab a hat-trick of tries for Rovers with Shaun Briscoe also crossing.
Castleford enjoyed plenty of success themselves with Brett Ferres, Stuart Jones, Rangi Chase and Joe Arundel all touching down.
And Tigers looked set to hold on for a draw until Dobson stepped up to score a 47-metre penalty with the final kick.
Joe Westerman opened the scoring with an early penalty but Hull KR grabbed the lead when Charnley went over in the corner.
Castleford hit back with a move which swept the length of the pitch and was finished off by the diving Ferres.
But their advantage was short-lived as Rhys Lovegrove and Dobson combined well to set Briscoe up to cross.
Charnley then extended Rovers' lead when he collected a kick from Dobson to touch down.
Arundel reduced the deficit when some sloppy Hull KR defending allowed him to walk a try in and Chase went over underneath the posts for the Tigers just after half-time.
That made the scores level but Rovers edged ahead again courtesy of a Dobson penalty before a Stuart Jones try put Castleford back in front.
Charnley claimed his hat-trick of tries when he collected another Dobson punt but Westwood's fifth successful kick of the afternoon levelled the score once more.
But Dobson sent over his long-range effort with the very last act of the game.
Hull KR coach Justin Morgan:
"We are in the play-offs now and that is a great achievement. The main thing now is to get some form on the board.
"We need to get some good back-to-back performances and when the play-offs start we need to be playing well. Our game sense is improving but our execution is letting us down at times.
"We need to improve before we start talking about the Grand Final."
Castleford coach Terry Mattinson:
"We made a lot of breaks and played some good rugby but we just could not finish them off. We just came up short again.
"We worked really hard to break Hull KR down but at the end of the day it has come down to a decision which did not go our way. And things are just not going our way at the moment.
"We are looking forward to the break and we need to get some of the bodies refreshed. They are running on empty at the moment and doing a wonderful job for us. But we need to regroup and the ball is back in our court."
Hull KR: Briscoe, Fox, Charnley, Colbon, Latus, Murrell, Dobson, Clinton, Fisher, Lovegrove, Newton, Galea, Watts.
Replacements: Wheeldon, Netherton, Hodgson, Mariano.
Castleford: McGoldrick, Dixon, Shenton, Arundel, Wainwright, Widders, Chase, Huby, Hudson, Sargent, Ferres, Clayton, Westerman.
Replacements: Snitch, Jones, Holmes, Walker.
Referee: Phil Bentham (Warrington)