Roger Federer's lead atop the ATP world rankings may have dwindled, but world number two Rafael Nadal says displacing the super Swiss remains a daunting challenge.
Spain's Nadal trails Federer by just 350 points as they head into the first ATP Masters Series event of the season at Indian Wells, where men's first-round play began on Thursday.
But defending champion Nadal said the sums that show him perhaps passing Federer after the Miami Masters that follows Indian Wells don't tell the whole story.
"I'm closer in ranking, but it's not closer when you know what I have to defend," he said of the points system that determines the rankings.
"Right now people speak a lot about that," the 21-year-old said. "The truth is that everything is very difficult."
Federer's 350-point bulge atop the rankings, in the wake of his first-round exit in Dubai, is the closest margin since Federer led then number two Andy Roddick by 350 points in May of 2004.
Federer has held the top spot or a record 215 straight weeks, while Nadal has been number two for 138 consecutive weeks.
After winning here last year, Nadal has 500 points to defend, while Federer only has to improve on his second-round showing here last year to gain ground and consolidate his position heading into Miami.
"Maybe this is not the moment for number one," Nadal said.
Federer is the top seed at Indian Wells for the fifth-straight year, and will be seeking to add to the titles he won in 2004, 2005 and 2006. He and Nadal are followed in the seedings by Serbia's Australian Open champion Novak Djokovic, Russian Nikolay Davydenko and Spain's David Ferrer.
All of the men's and women's seeded players in this 5.7 million-dollar hardcourt tournament have first-round byes.
Colombian qualifier Santiago Giraldo booked a second-round shot at Nadal on Thursday with a 7-6 (7/5), 6-4 victory over Austrian Werner Eschauer.
Italian Andreas Seppi earned a clash with Djokovic with a 4-6, 7-6 (7/3), 6-2 victory over Chile's Paul Capdeville.
In women's play, Romanian Ioana Raluca Olaru defeated China's Yuan Meng 6-4, 6-4 to line up a second-round match with top-seeded Serb Ana Ivanovic.
US wild card Ahsha Rolle advanced to a meeting with third-seeded Serb Jelena Jankovic with a 6-2, 6-2 victory over compatriot Madison Brengle.