"Against Mystics there were just a few errors in a row that set the momentum off for them and we couldn't quite get ourselves out of it quick enough."
The Magic beat the Tactix 71-48 in the opening round of the ANZ Premiership.
Kopua said not much needed to change on court but timings had been a focus in training this week.
"It's not rocket science we don't have to change too much it's just the execution of our game plan and being able to concentrate for 60 minutes," she said. "We've been looking at timings through court and just having the trust to let the ball go and know that your teammate will have your back."
Kopua will also be buoyed by the form of South African import Lenize Potgieter - recruited after a standout Netball Quad Series for the Proteas.
Potgieter is the equal leading shooter in the league - alongside Southern Steel's Jhaniele Fowler-Reid - with 227 goals at 92 per cent after five matches.
Potgieter said her level of play had lifted playing alongside the likes of Kopua.
"It's an amazing experience to train and be in Casey's presence. She has this attitude of never give up and if we're starting to slacken off she gets on our case, which is a good thing. It's great to be alongside her, train against her, have her as a captain and as a friend."
Tactix have struggled this season - yet to have a win - but Kopua said she was taking nothing for granted.
"They [Tactix] are a determined team and never give up. They are smart - we just need to be smarter than what they are," Kopua said. "They just have a give it all attitude and that's something that really gets them through the match.
"We're looking for a result and it's huge to get a result to give yourself and your team confidence. We are not doing anything massively wrong it's just little things that need to be fixed up but it's just having that confidence, even if you are losing, that you can get it back is by giving it a go."
ANZ Premiership - round five
Silvermoon Tactix v WBOP Magic, Sunday, Horncastle Arena, Christchurch, 2pm.
Te Wananga o Raukawa Pulse v SkyCity Mystics, Monday, TSB Bank Arena, Wellington, 7.30pm.
Northern Stars v Ascot Park Hotel Southern Steel, Wednesday, Vodafone Events Centre, Auckland, 7.30pm.