Before most of the qualifiers even got on the plane to China, world #1 Rafael Nadal pulled out -- the knee injury he sustained in Paris forced him to withdraw -- and was replace by the surging Gilles Simon. As a result former Top Dog Roger Federer took the highest seed to lead a round-robin grouping that included the two Andys -- Murray and Roddick -- as well as Simon. In the other, seemingly less stacked, half second-seeded Novak Djokovic joined Nikolay Davydenko, Jo-Wilfried Tsonga and Juan Martin Del Potro.
When play began on Sunday with the Gold Group taking the court first, things seemed to go as expected -- higher ranked Djokovic and Davydenko both won their matches while Del Potro and Tsonga, the last two to originally qualify for Shanghai, took the losses.
But on Monday when the Red Group began play, Gilles Simon notched his second victory over Roger Federer this year -- the man who barely made it to Shanghai remained undefeated against the four-time ATP Champ. And if that weren't enough, today Andy Roddick dropped out of his second match due to an ankle injury. He was replaced by 27th-ranked Radek Stepanek -- a strange logic I still don't understand, but that's a whole other issue -- who happened to be vacationing in Thailand at the time.
With two more days of round-robin matches left, so far Novak Djokovic and Andy Murray have secured spots in the semifinals. I would guess Roger and Davydenko will fill out the remaining two spots, but who knows? Del Potro is certainly capable of taking out Nikolay. And if Murray is successful against Federer -- he does, after all, have a winning 3-2 record against him -- while Simon continues his summer surge, things could get pretty interesting in the final weekend.
After all, where's the fun if there weren't some surprises?