Muscat: They're a whole new Adelaide
Victory were the last team to beat United, at a stage when the Reds had lost eight in a row, a far cry from their success of late.
"The way they (Adelaide) set up now, I suppose they're not pressing as high as they used to," Muscat said.
"Naturally there are risks that are associated in pressing high; you're a little bit more vulnerable with space.
"This way, the way Adelaide sit off - and it's working very well for them, so it's a positive from their perspective - they're a little bit more direct as well.
Muscat added: "When they win the ball back, in transition, they're a little bit more direct in not trying to keep possession for the sake of possession.
"They're a good team; they've got some form players, so we're going to have to be at our best tomorrow night."
Friday night's match will be one of five against current top-six sides as Victory are set to host Adelaide, Sydney FC, Western Sydney Wanderers and Brisbane Roar in their remaining home games.
"The beauty of that is that if you're winning games - and obviously that's our aim - you're taking points off the opposition immediately surrounding you, and vice-versa - there's a double-edged sword," Muscat said.
"So they're big games and that's where we want to be and that's how we want them."