Graeme Smith warned England on Wednesday his South Africa team were determined to take the hosts' number one ranking in Test cricket away from them.
If the Proteas win the upcoming three-match series, they will replace England at the summit of the International Cricket Council's standings.
South Africa captain Smith, speaking on the eve of the first Test, which starts at the Oval in London on Thursday, said his side's strong away record made them genuine contenders.
"We've been really consistent," said Smith. "Maybe we haven't got some of the victories we would have liked but away from home our record speaks for itself. In all conditions I think it's fair to say that we've been the most consistent team over a period of time.
"We're looking forward to getting hold of that ranking and performing well. This Test series offers us an opportunity."
England captain Andrew Strauss acknowledged the home team faced "a very strong challenge"
He said: "South Africa are a very fine side. They've proved that over the last couple of years and they'll be determined to knock us off our perch. It will be a good gauge for us. The rankings say we are number one and we have to go out and prove it."
Both Strauss and Smith said the controversy over Kevin Pietersen's England future, which rumbled on Wednesday when the South Africa-born batsman was omitted from the initial World Twenty20 squad, had had no bearing on either side's preparations.