Comfortably into her third decade on tour, Serena Williams remains the dominant power in women's tennis with her eyes firmly fixed on overhauling Martina Navratilova and Chris Evert's Grand Slam record in 2013.
The American, who will turn 32 in September, finished the year at three in the world.
She was in a class of her own in the second half of 2012, winning Wimbledon, the Olympics, the US Open and then capped it off with a stunning straight sets demolition of Maria Sharapova in the WTA Championships final.
"I definitely think I can improve some more," said Williams, who now has 15 Grand Slam singles titles.
That's just three off the 18 collected by Navratilova and Evert with only Steffi Graf's record of 22 looking potentially out of reach.
"The day I feel that I can't improve, I think that's the day I should probably hang up my racket," added Williams, whose success in the latter half of the year looked a distant dream in the first six months of 2012.
Having missed 12 months of action in 2010 and 2011, battling life-threatening blood clots on her lungs, she was a fourth-round loser at the Australian Open.
