Aces recently handed Ajax their first Absa Premiership loss of the season with a 1-0 scoreline in Nelspruit last week.
Nengomasha, however, says the Urban Warriors are typically better on their home turf, with Cape Town Stadium the venue for the upcoming rematch.
"We know the strengths and weaknesses of Ajax but most importantly, we know how difficult they are when they play in their own backyard in Cape Town," Nengomasha told his club's website.
"We know the strengths and weaknesses of Ajax but most importantly, we know how difficult they are when they play in their own backyard in Cape Town. We played them in Nelspruit last week and it was evident the heat took its toll on them so we obviously expect to find the going tough as well playing at sea level."
The former Kaizer Chiefs and Bidvest Wits man continued: "Whoever plays on Sunday will approach that game with respect because we cannot afford to take Ajax lightly simply because we beat them in the League last week. They are second from top in the League and that just highlights the dangers that Ajax possesses.
"We expect Ajax to come out guns blazing because they know we beat them just recently, but we will be ready. If I am in the team, I will fight for the shirt and make sure things go well for us."