The Warriors went back to the top of Super League, but only after an uneven performance that left unanswered the key question about Wigan this season: Can they play without Sam Tomkins?
Wembley-bound Wigan's coach, Shaun Wane, rested two of his blue-chip players, Pat Richards and Liam Farrell, and left out others with minor knocks. More dramatic was the last-minute withdrawal of Tomkins with illness.
Wigan made their breakthrough in the 14th-minute, with Josh Charnley's 28th try – the most in Super League this season.
The former Wigan player Michael Dobson supplied a perfectly-timed pass to put Greg Eden over in reply, Dobson's conversion giving his current side a narrow lead. Wigan were untidy with the ball and giving away too many silly penalties; it was not only Tomkins who was off-colour.
They were punished after 32 minutes, with Dobson this time spotting a gap in the defensive line and darting through to score. Wigan could still have been level if Epalahame Lauaki had not been stopped inches short of the line and Dom Crosby held up over it.
Just before half-time and after Hull Kingston Rovers had been harshly denied by a forward pass ruling, Matty Smith's grubber and Darrell Goulding's chase did – rather undeservedly – bring the Warriors level.
With the game in the balance, Rovers lost Lincoln Withers to the sinbin for a dangerous tackle. They got another decision they didn't like when Charnley was credited with a second try, despite the ball appearing to go into touch. It seemed a bizarre call by the video referee, James Child, but it did not dampen Rovers' enthusiasm.
On the contrary, another ex-Wiganer, David Hodgson, was denied an equaliser in the corner by a fraction. It was not until Anthony Gelling's try seven minutes from time that his old side began to feel safe, with Smith's drop goal taking out extra insurance, before Evarn Tuimavave got one back for resilient Rovers.
Wigan Hampshire, Charnley, Goulding, Gelling, Burgess, Green, Smith, Mossop, McIlorum, Taylor, Hansen, Tuson, O'Loughlin. Substitutes used Hughes, Lauaki, L. Tomkins, Crosby.
Hull KR Eden, Hall, Gleeson, Salter, D. Hodgson, Burns, Dobson, Paea, J. Hodgson, Walker, Lovegrove, Cox, Mika. Substitutes used Withers, Beaumont, Hepi, Tuimavave.
Referee R Silverwood (RFL)