The Warriors host the Sydney Roosters in Auckland on Saturday night after coming off their worst result of the season - a 36-4 loss to premiers South Sydney.
It was, Mannering admits, pretty disappointing to put in the performance they did in Perth after having travelled so far.
But the Warriors have done their reviews and moved on.
"You can't kick stones for too long," Mannering said.
"We've addressed where we need to improve. It's not about reinventing the wheel. It's about doing the basics a lot better."
The Warriors are level on competition points with the sixth-placed Roosters, who also lost last weekend, going down 10-4 to Cronulla.
But they sit two places below the Roosters on the ladder through a vastly inferior for-and-against, and the margin against Souths didn't help.
"We definitely have to aim up defensively," Mannering said.
"We leaked too many points against the Rabbitohs, and the Roosters are a team that compete right through the whole game."
Both the Warriors (Ryan Hoffman and Jacob Lillyman) and the Roosters (Michael Jennings, Mitchell Pearce, Boyd Cordner and Aidan Guerra) have players on Origin duty.
The visitors will also be without enforcer Jared Waerea-Hargreaves, the prop out with a calf complaint, which opens the way for Suaia Matagi to face his former club.
For the Warriors, Lillyman's absence means a promotion for young front-rower Albert Vete, who will partner Ben Matulino in the starting line-up.
While Matulino has been one of the form props of the competition, Vete has also impressed when coming off the bench in his debut season, as has fellow rookie Sam Lisone.
Coach Andrew McFadden said the home pack - who also include Raymond Faitala-Mariner, coming in as Hoffman's replacement and making just his second NRL appearance - knew the challenge before them.
He is confident they can hold their own at Mt Smart Stadium.
"Our young forwards have got no fear themselves," McFadden said.
"I expect them to stand up."
Fullback Sam Tomkins has been named to start after being a late withdrawal against the Rabbitohs because of a knee injury.
The inclusion of the England international, who is returning to Wigan at the end of the season, sets up an intriguing head-to-head duel.
Tomkins will be up against another big Warriors signing and the man who will replace him at the club next year, Roger Tuivasa-Sheck.
