United hasn't lost a W-League match since Sydney FC beat it 3-0 in January last year, but their 18-match undefeated streak hangs in the balance as the depth of its squad is tested.

Strikers Michelle Heyman, Ashleigh Sykes and Hayley Raso are unavailable, and centre-back Ellie Brush will serve a one-week suspension, leaving coach Jitka Klimkova with no choice but to take an inexperienced team to confront the Victory in Melbourne.

To make the task more challenging, Melbourne has added two international midfielders to its roster, Welsh captain Jessica Fishlock, Britain's reigning FA Women's Super League player of the season, and Swede Petra Larsson, a veteran of more than 80 matches in one of the world's best leagues, the Damallsvenskan.

''At some stage we're going to lose a game, that's reality, but the question is when,'' United chief executive Heather Reid said.

''There's no doubt that this is going to be a tough weekend, traditionally Melbourne has been very tough anyway.

''The fact they beat Sydney 2-1 is a sign that they're capable of really challenging for the title, so Jitka's certainly got some work to do.''

While Klimkova works out how United will match up with a new-look Victory, extending the undefeated streak is not her priority.

''No, absolutely - I really don't count the games, it's the game in front of us, it's Melbourne,'' she said. ''It's not about this [streak], or OK, now we should be worried about maybe we can be beaten, it's not about that - I don't think about it and won't encourage the team thinking like that.''

The reigning coach of the year is relishing the challenge and the prospect of the unknowns in her side. ''I love these situations where everything is a little bit open … it's great, I am positive person, I always try to find the positives in the situation,'' she said.

''It's a great opportunity to see the young players … I'm sure they will put everything on the field to do their best to stay on the field. Not just for this game, but to make a challenge for me for the team, to say 'we are ready, we want to play, we deserve to play in the W-League'.

''I know they don't have so much experience, so from my side there is not huge expectation of the best performance ever. But I just think it's a great opportunity for these young ones to just play their game.''

Melbourne will be without two Matildas representatives, goalkeeper Brianna Davey and fullback Stephanie Catley, but Klimkova is wary of the changes.

''They will be [have their] other goalkeeper, but maybe the second one can have the better game. The motivation of the players who don't play regularly can be much bigger than the others, so they can be the best on the field.

''Melbourne, with these two new players, is a really strong team. I know they had a little bit slower beginning of the league, but now we have to be really ready for their attacking style.''