By Ian Ransom
MELBOURNE (Reuters) - One of the few players with the game to trouble Serena Williams, Maria Sharapova's decade-long losing streak to the American great is one of the more curious anomalies in women's tennis.
Sharapova was a 17-year-old sensation when she last beat Williams at the title-decider of her debut at the season-ending Tour Finals in 2004.
That win followed her Wimbledon triumph a few months earlier when she shocked the American top seed in the final, a result hailed as one of the greatest upsets in the modern era by tennis writers at the time.
It has all been one-way traffic since with Williams notching 15 successive victories on all surfaces, a record that Sharapova has been reminded of, again and again, before her bid to break the streak in the Australian Open women's final on Saturday.
"I go into matches where I've beaten opponents and I don't want to focus on that because I don't want to get overly confident going onto the court," Sharapova said on Friday.
"But also it's tough knowing... that she has such a powerful game and I've had trouble against her.
"On the other side, when it's a final situation and knowing I'm a big competitor, I'll do everything I can to try and win the match."
Surprisingly, on paper, the defeats have not been hard-fought, as befits two of the toughest and most accomplished players in the women's game over the past decade.
Williams has often been known to drop a set here or there to far lesser opponents and crash out altogether at the grand slams, including her shock loss to Spaniard Garbine Muguruza in the first week of the French Open last year.
Against Sharapova, however, of their last 10 meetings only the 2013 final at Miami went to three sets, meaning the American always keeps her racquet sharpest for the Russian.
Both share the powerful ground-strokes and mental toughness of multiple grand slam champions.
They also have similar backgrounds, raised in humble circumstances and pushed into tennis by strong-willed fathers determined that they will succeed on the professional tour.
Away from the tour, the similarities disappear.
The pair have never been close and their personal differences exploded in the public sphere in 2013 when Sharapova made a tit-for-tat snipe at Williams' relationship with her coach Patrick Mouratoglou.
"If Serena wants to talk about something personal, she should talk about her relationship and her boyfriend that was married and is getting a divorce and has kids and not draw attention to other things," Sharapova told reporters before Wimbledon.
Williams has other incentives to keep the streak alive. A sixth title at Melbourne Park would have her move past Chris Evert and Martina Navratilova's record of 18 grand slam win and match American Helen Wills on 19.
From there, she would have a genuine shot at reaching Steffi Graf's professional-era record of 22 titles. Australia's Margaret Court holds the record across all eras with 24.
Williams would also become by far the oldest woman to win at Melbourne Park in the professional era, eclipsing the retired Li Na's effort last year at the age of 31.
A cold has been troubling her all week and she delayed a training session early on Friday before coming out for a hit later in the afternoon.
"I wasn't feeling really well," she said. "I got better, then I got worse this morning.
"It went well this afternoon, I felt better."
Sharapova is unlikely to take any comfort from that, having seen a gravelly-voiced and coughing Williams blow away her previous opponents at Melbourne Park.
(Editing by John O'Brien)