Philander capped off a momentous few days in which he became the fastest South African to take 100 Test wickets by ending Steyn's dominance of the rankings.
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Steyn has led the way in the standings since July 2009, only to finally be replaced after Philander claimed match figures of 7-129 in the drawn first Test with India in Johannesburg, which finished on Sunday.
Philander was quick to praise fellow paceman Steyn - who has taken 341 wickets in 68 Test appearances - and his team-mates after hitting top spot for the first time.
He said: "I am happy with my position as the number-one ranked Test bowler. It is an honour to have been bowling alongside a champion like Dale.
"It's been a great couple of years for our squad, and I have been fortunate enough to contribute to our success on the field.
"What has been the most pleasing though, for us, has been the all-round contribution from everyone in the squad that has been the main reason for our success over the last few years.
"Needless to say, it is always easier to be at the top of your game and successful when you are part of a winning team.
"Dale has been a tireless workhorse for us and continues to consistently put in quality performances for our team; it is no wonder that he was at the top of the bowling ranking for so long."