The Saints, who sacked Russell Martin recently, will take on the Premier League table-topping Reds.
"It's a great honour. I've worked at the club since the summer," Rusk said when asked about his feelings ahead of the game.
"I think this club has got a great tradition. The fan base is super committed and loyal and they'll be backing the players.
"For me, concentrating on that as my focus is the right, professional thing to do. I'm sure there's always a period of reflection after.
"It will be a proud moment for me, without a shadow of a doubt. It's a great honour, you know. It's a great honour to represent the club and guide them into such an important game."
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