Keiron Cunningham admitted he was left with a “headache” after their derby defeat.
A brief rally produced tries for second rower Joe Greenwood and stand-off Theo Fages, on his full debut, but they finished a clear second best.
Wigan had taken a 16-0 lead by half-time and claimed the bragging rights of their seventh successive Good Friday derby.
St Helens drop to fifth after a third defeat of the season and coach Cunningham admits he has work to do.
“I thought we started phenomenally well - it was probably one of our best starts of the year - but there were a couple of opportunities we didn’t take and one thing led to another,” Cunningham said.
“We put ourselves in a bad spot in the last 15 minutes of the first half. We got on the back foot and couldn’t get it back.
“Our left edge didn’t help us whatsoever, we’ve got to make sides earn tries. We need to have a good look at what we’re doing and that’s my headache to solve. We’ve got to have stability on both sides of the field.
“Some of the tries they didn’t have to earn, whereas we had to fight and scrap for everything we got so it’s disappointing but we get to go again on Monday.
“I can’t question the effort of the players in the second half, the guts and determination they showed to get us back into the game was brilliant but we’ve got to be a bit more ruthless as a team.”
The Warriors established a grip on the contest by half-time, when they led 16-0, but Saints restored some pride with a couple of second-half tries as they went down 24-12 in front of a full house at Langtree Park.
“It’s a great feeling, I just didn’t think the score reflected the game,” said Wigan coach Shaun Wane. “We got hammered with penalties, which put us under the pump and the 50-50s didn’t go our way,
“But I’m very proud. It’s a tough place to come. Saints are a well-coached team and they have some talent, so to get the two points means a lot to Wigan people.
“I thought we looked in control most of the time and it would have been a bigger win if we had been smarter.”