"Overall, I thought we played okay. The performance got better and better as the minutes went on.
"We take into account the fact we haven't played for seven weeks and the occasion, but I certainly feel as though those excuses have now gone."
Ryan Holden and Josh Smith were the goal scorers for the home team.
Athletic had to take the game to Stop Out in the second leg, Calvert said.
"Stop Out did what we thought they would do, which is to come out in a quick, intense way and try to undermine what the opposition's game plan is, and put them off it.
"Defensively, I thought we were all right.
"In the second half, we played a lot better and smarter on the ball."
Calvert said there was only one more chance to start the game right and the team had to take it.
"If we can do that, I've got all the confidence that we can do the job.
"I hope no-one is stupid enough to write us off after this one game, to be honest."
A nil-all or 1-all draw in Lower Hutt would result in Stop Out being promoted due to the two away goals they scored last weekend.
If it again ends at 2-2, the teams would head to extra time, then penalties if required.
"We're not desperate about having to score goals, but we know we can take their ascendancy out by scoring two," Calvert said.
"There has to be a purpose with how we play. They know that as well, and that makes for a really intriguing battle.
"It will be interesting to see if they do anything differently."
Athletic has hired a 49-seater bus to travel to Hutt Park on Saturday.
"We should have some really good support this weekend," Calvert said.
"There was a fantastic crowd at home as well. Both sets of fans were making a lot of noise.
"That was great to see on a sunny Whanganui day."
Whanganui Athletic play Stop Out Sports Club at Hutt Park on Saturday. Kick-off is at 2pm.
