Coach Mark Hetherington has stepped away from his role, so Berry and the senior players are filling that void.
With Jack Jonas and Kyle Graham returning to the side in the last two weeks, the team was shaping up nicely, Berry said.
They will look to reassert themselves as contenders in the YORB Horizons Premiership, after losing their last league contest 3-1 to Breakers Red Sox.
City sit fifth on the table, splitting their six games with three wins and three losses.
This weekend, they take on Palmerston North Marist reserves at Wembley Park.
Berry said the league was wide open this year, with five or six teams having a real shot at claiming the title.
"It's up for anyone. Whoever grabs it by the scruff of the neck and really wants it. We will look to make a run and get back up the top."
Athletic will cash in after having a week off and continue their steady climb up the table when they take on cellar dwellers Napier Marist.
They showed a lot of resolve in their last league meeting, a scrappy affair against rivals New Plymouth Rangers. Athletic scraped by with a 2-1 win, with both sides ending the match with 10 men.
Coach Tex von Kwiatkowski said the next two games against Napier and Palmerston Marist would play a pivotal role in their 2021 campaign.
"We win, we are back to being players in the league. They don't realise we are better than where we are on the table."
They have been defensively sound through five games, conceding just seven goals. It is on attack where Athletic have struggled, bagging just six goals over that time.
Von Kwiatkowski said developing their attacking philosophy and skillset had been a huge focus at training over the last two weeks.
Those scoring woes will only be amplified this weekend, where they will be without 2020 top goal scorer Josh Smith due to the red card he received against Peggy Gordons New Plymouth Rangers.
Injuries to starting fullback Ben Huijs and Wellingtonian Lukas Bayliss will see Athletic take a light squad of 12 players to Napier.
As the season goes on, they will slowly return to full strength.
Von Kwiatkowski said starter Will King was set to return from injury in the near future and defensive lynchpin Shaan Stuart would be back in New Zealand in July.
Napier Marist have not gathered a single point through five matches, and von Kwiatkowski knows how dangerous it would be to overlook them.
"I think they must have five or six players don't travel away games. If you look at their home results, they have all been pretty tight. It will be one of our toughest games.
"There are a lot of positives, but we are just lacking on numbers at the moment."
Athletic Reserves will look to right the ship when they travel to Palmerston North Boys' first XI this weekend.
Much like City, the team has struggled to find consistency after a strong 2020 campaign.
With two wins, draws and losses from their six games, this weekend's match against a young, high scoring side will show where they truly fit in what is shaping out to be a far more competitive competition than 2020.
Fixtures
Whanganui Athletic v Napier Marist at Park Island, Napier, Sunday, midday.
Wanganui City v Palmerston North Marist Reserves at Wembley Park, 12.30pm.
Athletic Reserves v PNBHS First XI at Memorial Park, Palmerston North, 12.30pm.
