ROME, Italy - Unsurprisingly, for two players who have spent most of their careers rubbing shoulders at the very top of the rankings, the vast majority of Serena and Venus Williams' 24 encounters have come at the business end of tournaments.
However, with Venus' ranking now too low to guarantee a seeded berth at the big events, Saturday's draw for next week's Internazionali BNL d'Italia has thrown up the possibility of the sisters' paths crossing at an unusually early juncture.
Should Venus make her way past the mercurial Laura Robson first up, Serena, the beneficiary of a first round bye, will be lying in wait. Aside from two round robin clashes at the season-ending WTA Championships, this will be the earliest the siblings have run into one another since a second round meeting at the Australian Open 15 years ago.
And the Williamses are not the only big names left slightly irked by the vagaries of the draw at the Foro Italico.
World No.4 Agnieszka Radwanska has been handed a likely second round encounter with Svetlana Kuznetsova - a player against whom she holds a miserable 3-10 head-to-head record - while Victoria Azarenka finds herself in a tricky-looking quarter that also includes Julia Goerges, Ana Ivanovic, Samantha Stosur and Petra Kvitova.
Maria Sharapova, the champion in both 2011 and 2012, is No.2 seed this time around and will start her campaign against a qualifier before a probable quarterfinal with Sara Errani.
Aside from Robson versus Williams, there are several other intriguing first round match-ups, including Carla Suárez Navarro against Nadia Petrova and home favorite Flavia Pennetta's meeting with Sloane Stephens.