McGuire landed the golden-point drop goal which snatched a remarkable 27-26 win over Castleford Tigers and edged the Robins a big step closer to Super League survival.
Rovers remain second from bottom, but joined Leeds Rhinos, Wakefield Trinity and Huddersfield Giants on 18 points, two clear of London Broncos.
The winner was McGuire’s third attempt at a one-pointer and Rovers’ fifth after Josh Drinkwater was twice off target.
Four of those came after Rovers had scored back-to-back tries late on to level the scores. In that frantic spell Peter Mata’utia was wide with a straight-forward penalty shot four minutes from the end of normal time, McGuire charged down Jake Trueman’s attempted one-pointer and Mata’utia failed to provide a pass when the same player was set a few metres out in the final seconds.
Tigers did not touch the ball in extra-time. They kicked-off, but McGuire booted a sensational 40-20 to carry the home side upfield and went for goal on the first play.
A draw would have been a fair result after a see-sawing encounter during which Rovers led 12-0 after only 13 minutes and were 26-12 down early in the second half.
Tigers had won their previous two games and, having ridden their luck. seemed well on course for a return to the top-five, making the most of their limited opportunities to take what should have been an unbreakable hold on a thrilling clash.
The Robins’ opening two tries both came from grubber kicks behind the Tigers line from half-back Drinkwater, the first touched down by Daniel Murray and Adam Quinlan reaching the second. Ryan Shaw added the extras to both, but Mose Masoe lost possession in the set from Quinlan’s try and Castleford struck straight back.
Again the try came from a kick, Mata’utia chipping through and winning to chase to touch down, before also kicking the conversion.
Quinlan was the victim of a high tackle which led to Rovers re-establishing their two-score lead through Shaw’s third goal, but Tigers responded with a moment of quality eight minutes before the interval.
There should have been nothing on for Jordan Rankin when he received Liam Watts’ pass 15 metres from the Rovers line, but his footwork took him past two defenders and he stretched over for a wonderfully-taken try which Mata’utia converted.
At the end of the next set Castleford came up with something just as good. Truman – who had handled in the previous move – kicked on the last and James Clare made an outstanding catch to touch down.
He was fouled in the act of scoring so Matautia added four points, from the conversion and then a penalty, to give the visitors a 20-14 lead at half-time.
Matters got worse for them at the start of the second period.
They dominated possession and field position for seven minutes, but then Mata’utia pounced on a loose ball, made some ground and supplied Greg Minikin who accelerated away for a try out of nothing. Ironically, Minikin is expected to join Hull KR next season. Matautia’s fifth goal of the afternoon left the Robins with a mountain to climb.
They didn’t get out of base camp until the 60th minute, when Chris Atkin split Castleford through the middle and Ben Crooks was in support to score against his former side.
Suddenly chins which had been dropping were back up. Shaw’s conversion made it a six-point ball game and, incredibly, the Robins were level within moments.
Jimmy Keinhorst’s clever run took them into the danger area, Drinkwater’s excellent cross kick was taken superbly by Crooks and Shaw landed the angled conversion to level matters with 16 minutes left.
Hull KR: Quinlan, Shaw, Crooks, Keinhorst, Hall, Drinkwater, McGuire, Masoe, Atkin, Murray, Tomkins, Hauraki, Lawler. Subs Hadley, Litten, Addy, Mulhern.
Castleford Tigers: Rankin, Clare, Minikin, Blair, Eden, Trueman, Mata’utia, Watts, Milner, Sene-Lefao, Holmes, McMeeken, Massey. Subs Millington, Maher, O’Neill, Clarkson.
Referee: C Kendall (Huddersfield).