Stepping up in place of suspended first choice Paul Izzo, Necevski made several saves to thwart Sky Blues attempts at building on Filip Holosko's first-half opener - the only goal in Friday night's win at Allianz Stadium.
Izzo has been in impressive form this campaign apart from his brain snap and subsequent red card against Melbourne City last weekend.
Now Okon will have to decide which of his glovemen to deploy in the club's next game against Adelaide United on March 25, but said the conundrum is 'great to have'.
"Paul's been very good this season and Ivan's a big reason as to why Paul's been good, because he's been pushing him," Okon said.
"I'm really happy for Ivan, he's waited patiently and it's never easy to come back to your old team in an important game, and he really stepped up."
Further complicating Okon's decision is Izzo's rumoured move back to Adelaide next season, though he was cagey on the suggestion Necevski - who saved a second-half Bernie Ibini penalty on Friday night - could now be prioritised with a view to the future.
"Right now I'm not even thinking about the game next week because we actually don't play, we've got a break," Okon said.
"It's been about performing every day, training, pushing each other, whether it's goalkeepers or outfield players.
"Certainly Ivan, I think he can really put his hand up for our next game at home against Adelaide in two weeks' time."