Usuthu edged the NFD strugglers 3-0 on penalties after 120 minutes of football produced a 2-2 scoreline at King Zwelithini Stadium in Umlazi on Wednesday.
Mnguni insists it was not easy going against Duncan Lechesa's hard-running charges.
"Eish, the game took me back to the NFD (laughs)," Mnguni tells KickOff.com.
"The NFD rush, chasing each other, counter after counter... in NFD there is no time to play the ball, it's not like in the PSL. In the NFD it's man to man, they stay with you. It's very rare to get enough time on the ball. So it was the kind of game that I'm no longer used to.
"But that said, it was a great game. Even now I'm still tired because the tempo of the game was too high. At the end we realised that to win this game we had to match their pace. We told ourselves that if they were going on 120 percent we must go on 130. We had no choice. They were always on top of us, and so we were forced to take the game to them. You must remember that in the NFD they only play on weekends, while we play every Wednesday and every Weekend. Maybe they even had enough time to recover."
The 25-year-old says spirits are high at the mid-table outfit as they look to go on a run in the competition.
"If we can just get to the top four and from there on we can try to reach the final. From there any team we can get we will be happy. As for our league form, credit should go to all the players as we are always pulling towards the same direction and the team spirit is also there, we work for each other."
The Newcastle-born player has scored twice this season and earned praise from pundits of late, but feels he is yet to reach his potential.
"Yes, people are happy that I'm performing but according to me I'm not yet where I want to be. There are a few things that I need to work on in my game then I will be satisfied."
Cavin Johnson's side will resume their league campaign against KwaZulu-Natal rivals Maritzburg United at Harry Gwala Stadium on February 16.