The perceived post-U.S. Open lull on the ATP Tour provided opportunities for some lesser-known players to make name for themselves, and two unheralded competitors did just that last week. Philipp Petzschner, a German ranked 125^th in the world, took home the title in Vienna while journeyman Russian Igor Kunitsyn, ranked 71^st, hoisted the trophy in Moscow.

Those surprises made for nice entertainment, but now it’s truly back to business. Heck, Petzschner and Kunitsyn were good enough to win ATP titles, but neither one came even close to getting into this week’s event. The first huge tournament since the U.S. Open is finally upon us as the Masters Series Madrid is already underway. Each and every one of the Top 30 players in the world (No. 31 Mario Ancic recently pulled out) is in the field. Yes, that means it’s time to fasten your seatbelts for the return of Rafael Nadal and Roger Federer.

Federer withdrew shortly before last week’s IF Stockholm Open, so he will be playing for the first time since Switzerland’s Davis Cup win over Belgium three weeks ago. The second-ranked Swiss won’t have long to get back in the swing of things, either, as he has been placed in by far the most difficult quarter of the draw. In round two he will face Radek Stepanek, a straight-set winner over Juan Monaco on Sunday, and his potential remaining path to the semifinals includes Jo-Wilfried Tsonga in the third round and either Juan Martin Del Potro or David Nalbandian in the quarters.

Nalbandian captured last week’s other tournament, the IF Stockholm Open, where he lost a mere 15 games in four matches before needing three sets to dispatch Robin Soderling in the final. The Argentine, however, has not been rewarded with a friendly draw in Madrid. He could open with Tokyo champion Tomas Berdych before meeting an on-fire Del Potro.

Novak Djokovic’s quarter also appears to have a number of potential winners, although the quality of the field is far inferior to that of Federer’s. The third-seeded Serb is surrounded by players looking to turn around recent slumps. Seeds Nikolay Davydenko, James Blake, and Ivo Karlovic have done nothing of late, and Djokovic has not exactly been setting the tennis world on fire himself. Indoor-court genius Robin Soderling, who finished runner-up to Nalbandian in Stockholm, could take advantage of a vulnerable section.

Meanwhile, Rafael Nadal are clear favorites in their respective sections. Nadal’s nearby seeds-David Ferrer, Stanislas Wawrinka, and Richard Gasquet-do not look overly ominous on paper, but the Spaniard will have to face Ernests Gulbis in the second round. The young Latvian, who played Nadal tougher at Wimbledon than anyone other then Federer, survived Nicolas Kiefer in round one on Sunday.

Murray probably has the easiest journey to the semis of all the top four seeds. Unless Marin Cilic returns from injury with a bang, the Scot should cruise into the quarterfinals, where he could face Andy Roddick, Fernando Gonzalez, or Gael Monfils.