The Wanderers' second 1-0 ACL win in a week has catapulted them to second spot at the halfway point of the group stage with a handy three-point buffer from the J-League giants.
Popovic's troops were forced to dig deep for much of the night at Parramatta Stadium but produced one of their most courageous performances of the season to topple Frontale.
It was the type of display the Wanderers have built their success on since their inception and one that has them well-placed to make it out of their tough group.
"When we lost out first game at home we were written off," Popovic said.
"This (Frontale) win Ieaves us in a good position at the moment but we also know in this competition you don't take anything for granted.
"We've tried to eliminate the mistakes, we're making teams earn their opportunities and we sit at the half way mark with a chance of getting through.
"That's what we hoped at this stage after having two home games out f three hope to be in a position that still alive and we are at the moment."
It took the Wanderers just three minutes to go ahead at Parramatta Stadium, with Labinot Haliti tapping in Tomi Juric's shot-come-cross.
Despite conceding large chunks of possession and territory in the second half, the home side's defence held firm to withstand Frontale's barrage.
Popovic was full of praise for his weary troops, especially the likes of Juric, Anthony Golec and Daniel Mullen who have played little football in recent months.
"We scored a very good goal and maybe we rode our luck at times near the end," The Wanderers boss admitted.
"But when you have a look at the team, Anthony Golec hasn't played an A-League game all year. Daniel Mullen hasn’t played since the first of November.
"It was Tomi's (Juric) first game back and he should never have stayed on for 90 minutes but had too because Daniel Mullen couldn’t run anymore.
"You've got Jason Trifiro, Labi (Haliti), Kwabena (Appiah), a lot of these players found it tough in last 20 minutes...unfortunately we couldn't take them all off but it was a fantastic achievement and effort from everyone.
"I'm very proud of them."
Frontale boss Yahiro Kazamo was disappointed with his side's slow start as well as their wayward finishing which cost them any chance of a result.
