Either Rafael Nadal or Roger Federer has been at the top of the world rankings since February 2004, while beneath this hegemony, Novak Djokovic and Andy Murray have each spent a bit of time at No 2, but largely at Nos 3 or 4.
It comes and goes at the pinnacle, but for the most part recently the top four have stubbornly refused to give ground unless Robin Söderling occasionally gatecrashes, as he has, significantly, by winning the Brisbane International last week.
Djokovic has enjoyed unbroken membership of the leading quartet for 3½ years, having had a decent stay at No 2 in the first five months of 2010. Back in Melbourne, three years after winning his only grand-slam title here, he looks as if