Maritzburg will battle Downs at Lucas Moripe Stadium this afternoon (15h00) for a place in the MTN8 semi-finals, alongside champions Bidvest Wits, Cape Town City and SuperSport United.
Defender Xulu, who once shone for the Brazilians, is looking to revive his career after barely featuring for Kaizer Chiefs in the previous two years.
"Sundowns are a good side and you know they're African champions. We'll just go there with all we've got to play to win since it's a cup game," says Rusike, who scored when the sides previously met in a 2-2 league draw at the same venue late last season.
"The good thing of this team is that everyone who has just come in are fitting in well with the rest of the players. We have now Siyanda Xulu, who has experience, and they are hungry to play today."
Maritzburg finished seventh in the Premiership in 2016/17 after narrowly surviving relegation the season before. Rusike says lessons can always be learnt.
"As the players there's always room for improvement. Last season we took that as the lesson and we take it and learn from it," he adds.