The Wanderers have conceded 13 goals in six games this season, equal with Perth Glory.

They have won just one game after downing Adelaide United 2-1 away in Round Two.

The Red and Black said general play had been acceptable adding his has been punished for sloppy mistakes.

“Our football is getting better each game, we need to marry the two now, the performance with the result,” Popovic said.

“We feel we’ve played well enough to get wins, but now it’s about executing better on the day and finishing the job off in a match.

“I feel in general we’re not defending badly as a whole, but the goals against column is not something that pleases me or the group.

“We’re getting punished for mistakes, instead of looking at it saying we’re unlucky and punished for every mistake, we have to try eliminate those mistakes and not rely on something going our way.”

It does not get any easier with the Wanderers facing Melbourne City on Friday night.

Popovic has ruled out key striker Brendon Santalab who picked up a calf injury in the first half in the 3-0 loss away to Melbourne Victory last week.

It leaves a level of reliance on Kerem Bulut and youngster Lachlan Scott up front should he be required.

And after looking fractured at times this season following the loss off Scott Jamieson (IFK Goreborg), Mark Bridge (Chiangrai United) and Nikolai Topor-Stanley (Hatta Club), Popovic still believed there was improvement on last season.

“(Players departure) that’s their reward for doing so well at the club, but trying to get 500 games of A-League experience into players is not easy,” he said.

“Then on the other hand you look at our football and you say in some respects I feel we’re playing with the ball better than we did last year so that’s pleasing.

Key midfielder Mitch Nichols described the sloppy play as “schoolboy errors” and admitted at times they were only putting in “a good 60 minutes”.

And while City and Socceroo star Tim Cahill lift attendances of opposition corwds, Nichols was not fazed by the visitors.

"It’s just another player on the night and we know his strengths so it’s just about us limiting the options for him,” Nichols said.

“There’s always a good turnout with the crowd, everyone knows the hype Timmy brings to the league and it’ll be good for the fans.

“Everyone knows Bruno (Fornaroli) has been banging in goals for fun at Brattsy (Luke Brattan) has been doing well.

“It’s really just us being on the front foot in the first minute. In the FFA Cup game we got bullied in the first half which never really happens to us.”