Halep upbeat despite Serena loss, ranking threat

World number one Simona Halep on Monday shrugged off a fourth-round loss to Serena Williams that ended her Australian Open hopes and threatens her top ranking.

The Romanian top seed lost 6-1, 4-6, 6-4 but remained upbeat after a gutsy display against 23-time Grand Slam champion Williams, who is on a mission this year for a record equalling 24th title.

Halep, 27, a finalist in 2018, arrived at Melbourne Park on a five-match losing streak, equalling the worst run of her career and trying to shake off a back injury that curtailed her season.

After appearing listless through the early rounds, the French Open champion lifted to defeat Venus Williams then played her best tennis of the tournament against Serena after weathering an early onslaught.

When asked to rate her campaign she replied: "Close to 10." "I have the courage to say that, because I took the risk to stay home so much (for off-season rest).

"I haven't prepared for the highest level in tennis, but I didn't play bad, so I'm happy about the way that it's been going this tournament. I take only the positives. I had great matches." Halep was not concerned her fourth-round exit could cost her the number one ranking, saying she preferred to concentrate on tournament results.

"The main goal is just to play as good as I can every match, to win every match I play, so the ranking doesn't really matter," she said.

"At this stage I have to work hard to get the level back, to feel 100 percent every match. So I'll work for that."