SANTA PONSA, Spain, — Former US Open champion Samantha Stosur says she is prepared to slog through qualifying draws to restore her ranking having slipped outside the world's top 100 for only the second time in 11 years.

The 35-year-old Australian, who reached No. 4 after stunning Serena Williams to win the 2011 US.Open, has fallen to 115th on the WTA list and could go lower after a second-round defeat by Elise Mertens at the Mallorca Open on Wednesday.

But she is far from downhearted and was already checking flights from the idyllic Balearic isle to the cooler climes of Eastbourne where she will be involved in the first round of qualifying on Friday.

Stosur is of the "glass half full" mentality, however, and rather than get down on herself, she is prepared to fight her way back up the rankings.

"Look, I still want to play and if that's the situation I'm in and I want to continue then that's what you have to do (play in qualifying draws)," Stosur told Reuters after a 6-3, 6-3 defeat by fourth seed Mertens on the Santa Ponsa grass.

"If you're playing well enough hopefully you're not doing it for too long. It's not ideal, but the aim is to try and work very hard to make the main draw at the US Open.

"It's not the place I want to be in but I feel that I'm on the right track and there is room for improvement. Maybe I see things a bit different nowadays to six or seven years ago."

Stosur is at least assured of a main draw slot at Wimbledon where she will hope to improve a puzzling record that has seen her never pass the third round in singles in 15 visits despite reaching three women's doubles finals and twice winning the mixed doubles on the London lawns.

"Mallorca has been a nice relaxed start to the grasscourt swing," she said. "All in all, being on the grass for five days it's going pretty well. Just finding a way to get the ball shooting through and hitting flatter."

Mertens will face American Sofia Kenin in the quarte-finals. Second seed Anastasija Sevastova thrashed Ajla Tomljanovic in the day's late match to book a last-eight clash with China's Yafan Wang.

Thursday's action is headlined by a clash between reigning Wimbledon champion Angelique Kerber and 2004 winner Maria Sharapova who is back after a six-month injury layoff. — Reuters (Reporting by Martyn Herman Editing by Toby Davis)