The host nation are certain to feel the weight of expectation when they play Mexico in front of a capacity Soccer City crowd.
An expected 85,000 fans will be in the stadium with millions more watching at home in anticipation.
Bafana Bafana have played just once at the revamped venue - in late May when they beat Colombia 2-1 with a slightly smaller number in attendance.
But, according to the Portsmouth defender, that match served as a good dress rehearsal and he now expects his team-mates to be fully ready for today's clash.
"It was an opportunity for us to come and play against Colombia here in the stadium, so that we could get the feeling as to how it's going to be," he said.
"We looking forward to the game. We've been through the feelings of how it's going to be.
"It's going to be important that we go out relaxed, but of course not too relaxed, and enjoy it."
Mokoena, who recently became the first South African to reach 100 caps, acknowledged that all the work done in recent years was now about to be put to the test.
He added: "This is the most important thing. It's obviously important to win the first game of a tournament.
"We have a great respect against Mexico. They are a fantastic side, but for us it's important that we go out there and give it our all.
"We need to win badly and we're going to make it difficult for Mexico.
"It's about us, it's about what we want and about making our country proud. The moment of truth has arrived."
Mexico coach Javier Aguirre was confident his side had the experience to overcome any nerves.
He added: "Let me tell you that my players have lots of experience.
"They've played with full houses, full stadiums, they've played in all sort of circumstances, they've been in the business for years now and also the younger players have plenty of experience.
"Of course there's a lot of emotion playing the opening game, but once you overcome all the butterflies in your stomach I'm sure Mexico will play very well."