Gatland praised South Africa as powerful opponents who are highly skilled at delivering their game plan.
He said: "They are very good at what they do. They put the ball up in the air and use power runners. We pretty well know what we are going to get.
"They'll play to their strengths and that's what they are good at doing. They are certainly a hard side to beat. But playing them first up in this competition is a great opportunity for us."
Speaking at the Wales team hotel headquarters in Wellington he explained that his Wales squad has benefitted from a strong build up across the summer and a successful series of summer international matches.
Gatland said: "It's been a great couple of months having the players together as a squad and we are pretty happy with the way the August games went. We are really in pretty good shape.
"The last three times we have played them there's been very little in the scores. We have scored them seven tries to six. Now we've just got to get over the final hurdle and get that win.
"We can match their forwards. We are going to put out the strongest side we can. I don't think that in the last few times we've played them we have been far away from them as a team."
Gatland added that Wales must focus on each pool game as they come and he is confident his team can do well. "It's one game at a time for us and we have got a squad capable of winning these games," he said.
"If we can get out of the group stage then we are in good shape for the quarters and even the semis."
His confidence was echoed by team captain Sam Warburton.
"I am quite excited by what lies ahead of us," said Warburton. "We had a really good summer and we have a squad capable of winning games. There's a lot of confidence in the camp. Training has gone well and the boys are in pretty good shape.
"We had a really great welcome at the airport when we arrived and now I am just looking forward to getting on the field again."
Fellow flanker Dan Lydiate spoke of his relief at being selected to represent Wales at RWC 2011 in New Zealand.
He said: "I am so pleased to be here and finally getting on the plane was such a relief. We've already trained and got that plane journey out of our systems. It seemed a long time coming but we are here now and ready to get on with the job.
"We just want to get to kick off and get the games underway. We have got to get our game heads on this week as this competition is the biggest thing in world rugby There cannot be a bigger rugby stage to appear on and we are all determined to do our very best."