Pienaar was the last of South Africa's players to join up with the squad preparing in Johannesburg for the tournament, given a week's extra holiday by coach Carlos Alberto Parreira after his exertions in the English Premier League this season.
"As an individual I have always believed in myself, and I hope in the national team I will carry on the way I finished the season at my club," he told a news conference on Wednesday.
Pienaar expressed confidence in the home team's ability to get past the first round, even though they are not expected to make a major impact.
"I rate our chances of doing well in the tournament very high, in fact I am very confident that we will go further than the second round. We are definitely ready to go because the confidence is there, the spirit is there and I believe we will do well.
"The team has been doing well and I have been following their progress since they started with the training camps (in March)," he added.
South Africa contest Group A with France, Uruguay and Mexico.
Pienaar said he hoped for a run out against Colombia in Thursday's friendly at Soccer City despite Parreira suggesting earlier he would only make minimal changes to the line-up that drew 1-1 with Bulgaria in Johannesburg on Monday.
Pienaar last played for his country in a friendly in Ireland last September.
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