The Warriors could have lost by two points and still advanced through to the NRL finals but a stumbling and stuttering effort saw them outclassed by a clinical Panthers outfit determined to book a top-four finish.
Mannering spoke of the pain of defeat after missing the finals for a third year in a row but conceded his side wasn't in the same class as the top eight teams.
"It hurts to get so close, yet with our performance tonight we didn't deserve to be there," Mannering said.
"We were just two points away from getting back in the finals after missing out the last couple of years. I still feel we should have given ourselves opportunities through the year to be in the eight but it showed tonight we didn't quite deserve it.
"That's unfortunate because we did work pretty hard but it obviously wasn't good enough. It will hurt the team, not getting any reward, and it's something we'll have to learn from for next year."
The Warriors are left to reflect upon another inconsistent season that left them with 12 wins and 12 defeats, and just four wins from 12 away starts, figures which expose their true standing as premiership pretenders.
"It's an average record which reflects us as a team unfortunately," Mannering said.
"We've shown at times that we can be better than average but we just haven't been able to do it consistently enough, which is a shame. As a group it's about getting those poor performances out of us throughout the year, not starting slow and coming back, so it's about playing more consistently throughout the season."
A disastrous start to the year saw coach Andrew McFadden replace former mentor Matt Elliott after five rounds (two wins and three defeats). Under his guidance the Warriors found confidence and went on to win seven out of their next 10 matches to resurrect their title hopes before dropping off to lose five of their final eight games.
Tellingly, those last three victories came against the sides propping up the bottom of the competition ladder -- the Titans, Raiders and Sharks.
"It's been a challenging year. Things got turned upside down pretty early but I thought we really handled that well as a club," McFadden said.
"We got it to a point where we were in with a chance but maybe all that pressure paid its toll in the end. We just ran out of juice at the pointy end of the season when we needed to come home with lots of energy and, in all honesty, we probably lacked that over the last month."
McFadden stressed the importance of having a full squad of 17 players equipped to play at their best week in, week out.
"There's definitely improvement in individuals in our team and for us to compete with the best teams we need a full team performance where everyone is competing at the top level."
Meanwhile, Warriors prop Jacob Lillyman has been included in the Kangaroos' initial train on squad for the upcoming Four Nations Tournament and Prime Minister's XIII match against Papua New Guinea.
Each week players will be added to the squad as teams are eliminated from the NRL finals series which starts on Friday night.
The Kiwis will name their initial squad for the Four Nations this week.
- David Skipwith of the New Zealand Herald
