Despite the outside noise surrounding the game, Northern Ireland left Croatia with a 1-1 draw after an injury-time own goal by Izabela Lojna, who also netted an early penalty for the hosts.
Reflecting on the game, Oxtoby said she was “positive” about the performance and she was confident her side could progress to the next round of play-offs.
If Northern Ireland triumph in Belfast on Tuesday, then they will likely face Norway for a place at the Euro 2025 finals in Switzerland next summer.
The hosts are boosted by the return of midfielder Joely Andrews, who missed the first leg through injury, while defender Rachel Dugdale will be assessed after picking up a knock in Croatia.
Linfield defender Abi Sweetlove, 18, has been drafted into Oxtoby’s squad as cover.
“I thought we dominated the ball and created loads of opportunities”, said Oxtoby, who added she has “selection headaches” for the second leg.
“We need to be a bit more clinical, which is some of the things that we have been discussing, but, apart from that penalty, I don’t think you can ask for much more.
“We need to make sure we convert that dominance with the ball in the final third into goals.”
When asked what will make the difference to produce a match-winning performance over 90 minutes, Oxtoby said patience will be key.
“If things don’t go your way in the first 20 or 25 minutes, then it’s about having the confidence and patience in what you are trying to do, that it will come.
“I’ve seen a lot of maturity from the group in that area. They have the patience to probe and try different things, and our principles of play have been really positive.
“It’s another opportunity to do that and I’m really excited to see how they go.”