MELBOURNE, Australia (AP) Serena Williams says she doesn't remember much about the first time she played Maria Sharapova at the Australian Open.

It was 11 years ago, after all, way back in 2005. But she does remember the outcome.

''I was down a match point. I remember hitting it as hard as I could,'' recalled Williams, who ultimately saved three match points in that semifinal. ''I remember, obviously, winning and that was really great.''

Sharapova remembers it, too. Mainly because her 17-match losing streak against Williams started that day.

Both players advanced Sunday to the Australian Open quarterfinals where they will meet in a high-profile rematch of last year's final and the latest installment in their long running rivalry.

''I look forward to playing the best in the world, and that's what she's proven in the last year - the last many years,'' Sharapova said about Williams after beating Belinda Bencic 7-5, 7-5 in the fourth-round Sunday.

Williams' dominance of the women's game has created a gulf that is enormous between her spot at No. 1 and everyone else.

She has won 21 Grand Slam titles, including last year's Australian Open, French Open and Wimbledon. She's won the Australian title a record six times in the Open era.

She came agonizingly close to winning all four majors last year, which would have made her the first person to complete a calendar-year Grand Slam in 27 years.

But losing, Williams said Sunday, just makes her want to win more.

''For my whole career, I have been motivated by losses,'' Williams said after beating Margarita Gasparyan 6-2, 6-1, in just 55 minutes. ''That's just been my thing. When I lose, I just get better.''

Williams has powered through the first week at the Australian Open without dropping a set. Asked if her record against Sharapova gives her extra confidence, she said it doesn't matter to her who she plays.

''I just feel like I'm really confident in my game right now, not against her or against any other opponent'' in particular, William said. ''I'm just really looking at me right now, and I feel like if I can just continue to play well, then it could be good.''

Put another way, when Williams is at the top of her game it is incredibly hard to beat her.

At 34, she is the oldest woman to hold the No. 1 ranking - but age does not appear to matter. Every tournament she plays in, it seems, holds another chance for Williams to make history.

With another championship in Melbourne, Williams would equal Steffi Graf's 22 major singles titles.

Margaret Court, the Australian great who won 24 Grand Slam singles titles and has a stadium named in her honor at Melbourne Park, was in the crowd watching Williams - and waved to her after the match.

''Obviously 24 is close, but, yet it's so far away,'' Williams said, adding that it was an honor to play in front of Court and she wasn't consciously trying to overtake her. ''Honestly, I just focus on each game at a time. I never play thinking I want to be with the great Margaret Court. I just play just want to win a Grand Slam and that's it.''

Before her match, Williams was keeping an eye on Sharapova's match and noted that she ''had a really good win today.''

Sharapova hit a career-high 21 aces and hit 58 winners, converting her second match point when she challenged a line call after her forehand was initially called long.

The five-time Grand Slam winner last won the Australian Open in 2008 and has been a finalist four times.

When her rivalry with Williams started out, she had the lead. Sharapova won consecutive matches against Williams in 2004, at Wimbledon and the season-ending championships, but hasn't won since.

It's a statistic she tries to block from her mind, particularly right before they play.

''It's not like I think about, `What can I do worse?''' Sharapova said. ''I got myself into the quarterfinal of a Grand Slam. There is no reason I shouldn't be looking to improve and to getting my game in a better position than any previous round. It's only going to be tougher, especially against Serena.''