The two teams will be looking are in line to win their second cup titles in their history ahead of the encounter on Sunday, with both having lost their respective league matches on Wednesday.
"It's a very tough assignment," said Mngqithi at the pre-match press conference on Thursday.
"If there is any game, I don't like in football is back-to-back matches, they always tend to give indifferent results.
"We are playing against a very good team, they may have not done well in their last two matches in the province, but they are still a very formidable team that has a lot of good things that they do."
The two teams met last Sunday in a one-sided Betway Premiership clash with Arrows hammering the visitors 4-0 at the King Good Zwelithini Stadium in Durban.
"In my opinion, [Gallants] probably ranked three or four amongst the well-coached teams in the league, yes, they have shortcomings here and there, but I rate them very highly and am expecting a completely different game from the game that we played last week."
Kick-off is at 15h00.
Marumo Gallants coach Alexandre Lafitte says the 4-0 defeat to Golden Arrows in the Betway Premiership last weekend is motivation to reach the Carling Knockout final.
Siwelele head coach Lehlohonolo Seema has singled out midfielder Grant Margeman for praise following the 2-0 Betway Premiership victory over Stellenbosch in midweek.
Miguel Cardoso says Mamelodi Sundowns need to build on their 1-0 midweek win over TS Galaxy to make up for a poor start to the Betway Premiership campaign.
Mamelodi Sundowns coach Miguel Cardoso has praised Sphelele Mkhulise's influence and professionalism, describing the midfielder as a player who represents the very identity of the club.
