Wigan Warriors kept alive their bid for the League Leaders' Shield with an impressive derby win against St Helens at the Totally Wicked Stadium.

With a four-point deficit to make up, the Warriors knew anything but a victory would all but hand Hull KR the trophy before they face Hull FC in their own derby on Sunday.

Saints dominated early on as a Deon Cross try put them ahead, but Wigan showed their pedigree as reigning champions by clawing their way back into the game as tries from Jake Wardle and Liam Marshall, and Harry Smith's penalty, gave them breathing space at half-time.

Jai Field's brilliant length-of-the-field try sealed a win which meant KR - who are top by two points - need to beat their neighbours at Craven Park to effectively take the Shield, although mathematically they would still need another victory.

Wigan knew topping the table was something of a pipe-dream with long-time leaders Hull KR having three games to secure the two wins they need to add the League Leaders' Shield to the Challenge Cup they won in June.

Their prime aim was to build momentum going into the play-offs, and with the mercurial Bevan French back to something like his best after a long injury lay-off, and with head coach Matt Peet having restored their defensive solidity, they are in good nick as they seek to defend their title.

It did not look that way in the opening 20 minutes as Saints stormed on to the attack, with St Helens-born Cross darting over from a superb looping pass from Jack Welsby.

Wigan girded their loins, however, and Liam Farrell's break set up a Jake Wardle try, before Marshall capitalised on a successful leap and overhead pass from Junior Nsemba to add another.

Smith kicked the extras and a penalty to give Wigan a cushion at half-time, and they were not to be denied in the second half.

The key moment came as Saints pressed hard to get back into the game but Mark Percival's grubber kick went badly wrong as French dived on it and brilliantly passed off the floor to Field, who raced away with Saints' players trailing in his wake.

St Helens head coach Paul Wellens told BBC Radio Merseyside:

"It was a frustrating evening because the way we started the game was really good. We lined up a little bit differently given the circumstances with not having Morgan [Knowles] and George [Delaney] there, and it worked well early on.

"What hurt us was a lack of smarts. We were doing our damnedest to execute the game plan, particularly with ball in hand, but we did things in and around that which just put us under immense pressure and limited our ability to do what we'd practised.

"We delivered on 90% of what we'd spoken about during the week, but it's that final 10% that's really hurting us."

Wigan Warriors head coach Matt Peet told BBC Radio Manchester:

"I'm proud of the team, it was an important two points. It was a strange game - it didn't seem set-for-set that much for a Wigan-Saints game.

"They threw a bit at us, but we defended comfortably for most of the game. Once we started turning them around and making it set-for-set, we were the better team."

[On French pass and Field try] "That's what they're capable of. Jai had that moment where he combined with Bevan, but some of the kicks he fielded under pressure … both full-backs got peppered and I'm so proud of Jai."

St Helens: Sailor; Feldt, Robertson, Percival, Cross; Lomax, Mbye; Walmsley, Clark, Lees, Batchelor, Whitley, Welsby.

Interchanges: Sironen, Bell, Paasi, Burns.

Wigan: Field; Eckersley, Keighran, Wardle, Marshall; French, Smith; Hill, O'Neill, Byrne, Walters, Farrell, Ellis.

Interchanges: Havard, Thompson, Nsemba, Leeming.

Referee: Jack Smith.