Adrian Lam told his players "not to stress" about their tired attack as they laboured to an 18-8 win against London Broncos.
The Warriors came from behind to claim their third straight win to move to within two points of the top-four.
And Lam thought the lack of urgency was down to the congested Easter schedule rather than a lack of effort.
"It wasn't the prettiest game but we sort of expected it," he said. "It was frustrating to watch.
"I was okay with the attack, we've had four games in 13 days so I told the players not to stress about it.
"I know the public want to see more of (the attack), it's what I'm about, but in the circumstances it's important we win those kind of games and our defence was exceptional."
Wigan trailed 8-6 after a first-half desperately lacking urgency before converted tries from Chris Hankinson and Morgan Escare put them in control.
Lam has the benefit of a 10-day window before their next game, against Warrington in the Challenge Cup.