Western United coach John Aloisi has backed battling star defender Leo Lacroix to rediscover the form that made him the bedrock of their breakthrough A-League Men championship.

Lacroix scored a horror own goal early in United's 4-0 loss to Melbourne City on Saturday night, his third in just nine games this season, and almost scored another in the second half.

The 30-year-old also picked up a two-game suspension for a red card against Perth Glory and appears a shadow of the player who starred last season.

United are sitting 10th and have conceded 23 goals in 11 games.

"It's hard for me to say what's going on with the individual because I don't live with them, I don't see what they do day to day," Aloisi told reporters.

"But it's plain and easy to see that certain individuals aren't at their best like they were last season and Leo is one of them - he'll be open and honest about that.

"But we need to make sure that we're get him back to a level that he was playing at last year. He showed what he is capable of doing, he showed that he can do it.

"So that's up to us, up to me, to help him through this bad period that he's going through in terms of his performances and if we can do that, then we'll be a much better team."

Aloisi said Lacroix had been training normally and hadn't had any serious knocks or injuries contributing to his form slump.

"You just have to try and work with them, make sure that they're doing the right things in training, keep on working hard on the basics in training," he said.

"Once you do that, then normally, with a couple of good performances you can turn it around pretty quick.

"Leo's an older, experienced player so I'm sure that he will turn it around this season."

United will sweat on Ben Garuccio's calf injury but are hopeful James Troisi (calf) will be back in the next couple of weeks, though Steven Lustica is at least another month away.