Serb Jelena Jankovic has rediscovered her form in time for the U.S. Open, while compatriot and fellow former world number one Ana Ivanovic is still looking to turn her season round.
Jankovic, who ended last year at the top of the rankings, struggled for the first half of this year but by winning the Cincinnati Open earlier this month the world number five feels her game is back on track.
"I'm recharged," the 24-year-old, who overcame world number one Dinara Safina in the final to claim her second title of the year after victory in Marbella in April, told Reuters.
"I know I can play and move well and compete with the top players as good as I was, if not better. The U.S. Open is my main goal."
Jankovic has blamed her sluggish start to the year on an off-season training programme where she put on an extra 15 pounds of muscle, which she said had slowed her down.
"Every year I was making improvement and last year finished strong and I was beating all the top players and I was starting to dominate women's tennis," she said.
"I could hit harder but I lost explosiveness and in tennis, that's the most important thing."
She consequently struggled at the grand slams, falling in the fourth round in Australia and France and being knocked out in the Wimbledon third round by qualifier Melanie Oudin.
"I was playing without enjoyment and I had no passion and if you aren't passionate and having fun it's not the same," she said.
LOOKING FOR ANSWERS
Fellow Serb Ivanovic has had a similarly lacklustre year but has not yet shown the same signs of recovery as Jankovic.
The 21-year-old has not won a tournament since October 2008 and she said she had not been happy with her play since she reached the final at Indian Wells in March.
Her French Open defence ended in the fourth round in May and she retired injured at the same stage at Wimbledon in June, while her U.S. Open preparations have been shaky as she suffered early exits at the Cincinnati Open and Toronto Cup.
"I maybe made a little mistake because when, all of the sudden, I wasn't doing as well, I started looking for answers in all the wrong places," the world number 11 told Reuters in an interview arranged by WTA Tour sponsors Sony Ericsson.
After hiring coach Craig Kardon for four months, Ivanovic parted ways with the American in June and is now working once again with Sven Groenefeld, who helped her during the 2008 season, as well as Andre Agassi's former coach Darren Cahill.
"I want everything to be perfect, but it can't happen," said Ivanovic, who has never gone beyond the U.S. Open fourth round.
"When I try to go toward perfection I think I can stop myself now."
An inconsistent serve and her inability to consistently impose herself on opponents with her big forehand have troubled Ivanovic.
Ivanovic would like to reach the second week of the U.S. Open, which starts on Aug. 31, but is focused on a road towards long-term success.
"I found the path that I want to take," she said. "There are lots of new things in my game that I found work well for me, and have full confidence in this."