The Dube Birds will tackle Nedbank Cup holders Matsatsantsa at Orlando Stadium on Saturday evening.
And although Swallows lost 3-2 to visiting University of Pretoria in the Premiership last Friday, Marques suspects his men will be better focused against Gavin Hunt's outfit.
"It was one of those games where the players' minds were perhaps in the cup final," Marques said in the Sowetan.
"You can't really blame the players for thinking this way sometimes. The next game is a big game for us. It's huge for their careers and for the club."
Marques will expect his charges to improve their defending against United, who plundered three unanswered goals at AmaZulu's expense this past weekend.
"We showed character and we were unfortunate to concede a third goal. We conceded silly goals because of defensive errors," he added.