1) Nine and counting
This October, Williams will compete in the WTA Finals for a ninth time. She made her debut at the season-ending showpiece, then held at Munich's Olympiahalle, in 2001.
2) In search of number five
In her previous eight visits, Williams has won four titles (2001, 2009, 2012 and 2013). Only two players have won more titles at the Finals - Steffi Graf (five) and Martina Navratilova (eight).
3) Hunting down Martina
Williams has made the tournament her own in recent years, triumphing in 2012 and 2013. In fact, having missed out through injury in 2010 and 2011, she is unbeaten at the event since a round robin loss to her sister, Venus, in 2008. This run stretches 15 matches and is only bettered by Navratilova, who won 21 in a row between 1983 and 1987.
Victory in Singapore will also see Williams become just the third player to win three consecutive WTA Finals. The others were Monica Seles (1990-1992) and Navratilova (1983-1986).
5) Age no barrier
Since hitting her 30s, Williams has been playing some of the best tennis of her career. In Singapore, she will be 33 years and one month old and will be looking to break her own record as the oldest winner of the tournament.