England duo Sam Tomkins and Josh Charnley were also among the tries as Wigan demonstrated their class, but they were forced to withstand a late fightback from their injury-hit opponents before clinching the win that knocked Catalan Dragons off the top of the Super League table.
Dom Crosby also crossed for the Warriors, while second-half tries from Saints trio Paul Clough, Francis Meli and Tom Makinson kept their side in the game until Richards went over for his second try fives minutes from time.
Huddersfield wasted the chance to go back to the top of the table when a Marc Sneyd drop goal clinched a shock 21-20 win for bottom club Salford.
The Giants were never in front but hit back to draw level at 20-20, tries from Shaun Lunt, Jermaine McGillvary, Craig Kopczak and Danny Brough cancelling out scores from Lee Gaskell, Jodie Broughton, Ashley Gibson and Jordan James.
However, Reds full-back Sneyd coolly landed a one pointer eight minutes from time. It was Huddersfield's second successive defeat after a 28-2 loss at Warrington and they can have no complaints with the result.
Widnes pulled off a derby shock as they toppled high-flying Warrington 38-32 in front of a capacity crowd at the Stobart Stadium.
Rhys Hanbury and Paddy Flynn crossed for two tries each and Pat Ah Van landed seven goals and a try himself, but it was the power in the pack from Hep Cahill, Jon Clarke and the outstanding Gareth Hock that gave Widnes the edge and paved the way for victory.
Warrington did not bring their best game and Widnes made them pay as they climbed to ninth place in Super League table.
In the first competitive Hull derby of 2013 Hull KR cruised to a 23-10 victory despite the absence of Michael Dobson and a second-half injury to Travis Burns to see off Hull FC in an intense encounter at the KC Stadium.
The Robins built a 12-point first-half lead on the back of three crucial handling errors from the hosts in their own half. Josh Hodgson was on hand to grab the first and namesake David Hodgson dived over for the second, with Craig Hall adding two goals.
A Ben Crooks try reduced the deficit back to eight points just after the break, but David Hodgson's converted second try restored the visitors' advantage. Later on Kirs Welham added a try and Hall a drop-goal before Danny Tickle grabbed a late consolation.
Friday night's west Yorkshire derby at Castleford was abandoned in confusing circumstances with seven minutes left to play.
Wakefield had just scored their sixth try to lead 37-16 when spectators were told to evacuate the Princess Street Stand. The club issued a public call for an electrician and the fire brigade were summoned. Referee Ben Thaler had stopped play and, after a delay of around 10 minutes, blew for full time.
If, as seems certain, the result is allowed to stand, it condemns the Tigers to the foot of the table for the first time this year after going down to a fifth successive defeat.
- Sports & Recreation