Steve McNamara’s spell at the eighth-placed Dragons was ended by a 40-0 hammering at St Helens, and Tomkins shuffled the pack for his first game, giving a debut to 20-year-old winger Clement Martin.
The hosts bossed territory for long spells in the first half, but lacked the spark to break down some dogged defence. In contrast, a below-par Wigan made the very most of their attacking moments in a seventh straight Super League victory.
Catalans fell behind inside four nervy minutes when Field accelerated through a gap and ran 40 metres to the posts for his 15th try of the season in all competitions.
The Warriors went further ahead through a penalty kick from Adam Keighran, who landed eight of nine attempts off the tee.
It looked all too easy for Wigan when play was spread to the left where Marshall sprinted into acres of space and gave a simple scoring passing inside to Walters.
While the champions were ruthless and opportunistic in attack, they were also error-prone, at one point coughing up three successive repeat sets deep in their own half.
But Catalans failed to exploit the gifts, and indeed fell further behind when Marshall intercepted Theo Fages’ long pass and sprinted 90 metres to the line.
There was more good news for the visitors when Ethan Havard came on for his first action after four months out with a torn hamstring, but within minutes they lost Walters to a leg injury after a brief cameo from the bench.
