That leaves an opening for several players. Serena Williams will never be at her most comfortable on clay, but she is a former Roland Garros champ (’02) and has been playing top-3 tennis all year. Safina, who is having a career week and plays Elena Dementieva in Sunday’s Berlin final, snapped the American’s 17-match winning streak in the Berlin quarters.

The favorite going in might be last year’s runner-up Serb Ana Ivanovic, though she took a tough loss to a resurgent Dementieva in the Berlin semis. I’d add Maria Sharapova in my short list of potential winners, even though she, too, isn’t at her best on dirt. But all three of these big hitters – Serena, Ivanovic and Sharapova – could storm to the title if they get hot.

On the men’s side, Nadal’s wins at Monte Carlo and Barcelona indicated he is back where he usually is at this time of year – nearly invincible. But despite a solid season that has him atop the ATP Race, Juan Carlos Ferrero’s defeat of a blistered Nadal shows that he is beatable, especially after Ferrero went down the next round to Rome finalist Stanislas Wawrinka. Top-ranked Federer, meantime, is still formidable on clay (he lost to Nadal in the Monte Carlo final) but hasn’t showed the dominant form of the last four years. His loss to Radek Stepanek suggests he is a bigger question mark heading into Paris this year.

Novak Djokovic, even if he loses the Rome final Sunday (which I don’t see), should be around the final weekend in Paris. He has the tools, stamina and confidence on clay as he showed by reaching the final four last year. He has sometimes come up short in the heart department (see his semifinal retirements against Nadal at Roland Garros in ’07 and against Federer in Monte Carlo two weeks ago), but I like his chances more this year. A handful of other great dirtballers – ATP match leader on clay Nicolas Almagro, fellow Spaniard David Ferrer, two-time French Open semifinalist Nikolay Davydenko and even unpredictable David Nalbandian could do major damage, or more.

Nadal, who has never lost at Roland Garros, remains the clear and strong favorite, and the extra rest following his second-round loss at Rome might be a blessing in disguise. But I just sense that his aura of invincibility, like Federer’s, has slipped a tad.

U.S. Men Looking Up

I’m encouraged by results from the U.S. men in Europe so far. Sam Querrey, 20, reached the last eight at Monte Carlo, a breakthrough result on clay. James Blake reached the Houston final (which he should have won) and then quarters in Rome this week, posting decent wins over Andreas Seppi and Fernando Verdasco, though it looked like he ran out of steam against former Roland Garros junior champ Wawrinka of Switzerland 6-7, 7-6, 6-1. Andy Roddick, meantime, blasted his way into the Rome semis, improving to 8-0 against Tommy Robredo of Spain in a tight 6-3, 4-6, 7-6 win Friday.

How significant are these results? Consider that Andre Agassi was the last Yank to reach a masters on clay, doing so at Rome in ’05. The last time two or more American men reached the quarterfinals of a clay Masters was six years ago, also at Rome, when Agassi won, Roddick reached the semis and Blake reached the quarters. Maybe an American can make it into the second week in Paris. It couldn’t get worse than last year, when the USA men went 0-9.

More trouble for De Villiers?

A source in Rome tells me that the Players Council voted this week to take down ATP Chairman Etienne de Villiers and the three players’ reps on the ATP board, which if nothing else, is a vote of no-confidence. De Villiers, meantime, threatened to resign. Stay tuned on this unfolding acrimony between the players and ATP leadership (and see my earlier blog of Thursday, April 10, for more background).