California: World number ones Rafael Nadal and Caroline Wozniacki lead a world-class field into the $4.5 million BNP Paribas Open, a combined WTA and ATP Masters series event that begins on Wednesday.
Instant replay will be available for the first time on all eight competition courts at the desert resort oasis, where Croatia's Ivan Ljubicic and Serbian Jelena Jankovic will defend their crowns.
Women's main draw matches begin Wednesday while the men start on Thursday. In each case, top seeds have first-round byes, pushing the debut matches for most of the major stars to the weekend.
Nadal, a nine-time Grand Slam champion who won 2007 and 2009 Indian Wells titles, ended a five-week layoff last week in a first-round Davis Cup tie and seeks another deep run after losing to Ljubicic in last year's semi-finals.
Nadal could join US legends Jimmy Connors and Michael Chang and Swiss world number two Roger Federer as a three-time winner at Indian Wells.
Federer, a 16-time Grand Slam singles champion, comes in off a loss to third-ranked Novak Djokovic in the Dubai final and a week of workouts to prepare himself for the challenge of the US hardcourts.
"I feel like I need more practice, just a little bit here and there," said Federer. "It's going to be different conditions again. It's going to be flying but it's going to be slower. So it's going to be a challenge to balance those two things in Indian Wells."
Federer is 29-7 lifetime at Indian Wells and is the only player to win the event three times in a row, his title run coming from 2004 through 2006.
Djokovic, the 2008 Indian Wells champion, is on a 12-match win streak after capturing the Australian Open and Dubai titles.
The Serbian star would replace Federer as world number two headed into the Miami Masters event later this month if he wins the Indian Wells title, reaches a final not against Federer or reaches the semi-finals with Federer ousted before the quarter-finals.
"I feel physically well, fit, and mentally motivated to do even more coming up to Indian Wells and Miami, where I haven't done well in the last years," Djokovic said. "I really want to work hard and get some good results in the US."
Sweden's Robin Soderling has won three titles this season and risen to fourth in the rankings, just ahead of Scotsman Andy Murray, who reached the Australian Open final but comes to Indian Wells still in search of his first Grand Slam crown.
"I think the top-five players have played really well the last six months," Federer said. "Someone always has to win. At the end of the day, we've been able to share those a little bit to be honest.
"Rafa still is the favorite. He has won three of the four Slams. Novak maybe has not lost a match yet this season, but the season is still really short. I've been playing well. Murray has been playing well. I think we'll know more sort of after Wimbledon. But I don't expect any crazy changes at the top."
Wozniacki, who lost to Jankovic in last year's Indian Wells women's final, won six titles last year and another crown last month at Dubai after losing in the Australian Open semi-finals, keeping the great Dane without a Slam crown.
Second-ranked Kim Clijsters, the 2003 and 2005 Indian Wells champion, is coming off a victory over China's Li Na in the Australian Open final, the Belgian taking her third Grand Slam title since a 2009 return from a break to start a family.
Russian Vera Zvonareva, the world number three who won at Indian Wells in 2009, is joined among the favorites by fourth-ranked Australian Samantha Stosur, fifth-ranked Italian Francesca Schiavone, sixth-ranked Jankovic and seventh-ranked Li, the first Chinese player to reach a Grand Slam final.
"Australia is over. Now I have to start all over again," Li said, mindful of first-match exits last year at Miami and Indian Wells.
"Last year I didn't do well in Indian Wells and Miami. I think I am a good player, but I forgot how to walk on the court. Now I have more experience. I know what I should do on the court."
Other top players in the fields include past Indian Wells winners Maria Sharapova of Russia and Lleyton Hewitt of Australia.