The ATP’s abbreviated Asian swing culminates with the eighth Masters 1000 tournament of the year in Shanghai.  Chronically hampered by withdrawals and retirements, this youngest of the elite events hosts its fifth edition in 2013.  Beyond the injured Andy Murray, all of the top 20 men have entered. 

First quarter:  Never in the 2013 season have Novak Djokovic and Roger Federer renewed their once-bitter rivalry, filled with epic encounters on the grandest stages.  This pair of champions could meet again in a Shanghai quarterfinal, their earliest meeting in any draw since February 2007.  Few dark horses might bar their paths to that rendezvous, although Federer has suffered some perplexing losses this year.  He never has lost to ninth seed Richard Gasquet away from clay, however, nor has he lost to Lleyton Hewitt away from grass in nearly a decade.  Gasquet faces an intriguing opener of his own against rising Canadian Vasek Pospisil, still a work in progress but armed with the quick-strike game that can disrupt the Frenchman’s timing.  Aligned to face slumping compatriot Janko Tipsarevic in his opener, Djokovic would face one of several clay specialists in the round before Federer.  While Tommy Robredo reached a US Open quarterfinal, he would need significant help from the Serb to score the upset.  The slow surface in Shanghai should favor defending champion Djokovic over Federer, as should their 2013 form overall.

Second quarter:  Of the four seeds in this section, one relies on explosive firepower and the others on a patient counterpunching style.  Seventh seed Jo-Wilfried Tsonga, the flamethrower here, flamed out of Tokyo last week as he searches for rhythm early in his comeback.  The most impressive of the counterpunchers this fall hails from the same nation as Tsonga and defeated him last month in Metz.  Winning the title there, Gilles Simon reached the semifinals in Bangkok a week later before injury sidelined him again in Tokyo.  If he brings full fitness to Shanghai, Simon should feel confident of upsetting world No. 4 David Ferrer in the third round.  He won their only hard-court meeting two years ago, and Ferrer has looked a shadow of himself throughout the second half while struggling against the most pedestrian of journeymen.   Tsonga’s personal kryptonite arrives in the third round as well, represented by Kei Nishikori.  The Japanese star has flummoxed the Frenchman in both of their previous meetings, although he must dodge the bullets of Grigor Dimitrov in his opener.  Tokyo semifinalist Ivan Dodig and Kuala Lumpur runner-up Julien Benneteau add subplots to this open section.

Third quarter:  In the absence of Murray, world No. 5 Tomas Berdych earns the chance to reach a Masters 1000 semifinal without facing any member of the Big Four.  Whether he can exploit that chance remains less certain.  After a strong start to the fall, Berdych withdrew from a Beijing semifinal on Saturday with a back injury.  Of greater concern may be his 2-4 record against potential quarterfinal opponent Juan Martin Del Potro, although Berdych won their only meeting on an outdoor hard court five years ago.  Those looking for an early upset might eye a first-round meeting between Tommy Haas and Sam Querrey.  While 11th seed Haas fell in the first round of Beijing last week, Querrey reached his second straight quarterfinal.  Del Potro should handle the winner of that match comfortably, though, as Berdych looks to extend his mastery over Nicolas Almagro.  Since a controversial incident at the 2012 Australian Open, they have met five times with the Czech winning four.  But the Spaniard reached the Tokyo semifinals last week, forcing Del Potro to two tiebreaks there, so Berdych cannot overlook him.

Fourth quarter:  Back at the pinnacle of the ATP, Rafael Nadal holds the second seed in a draw for the last time of 2013.  He never has lost to any of the seeds in his section, even winning all 22 of the sets that he has played against world No. 9 Stanislas Wawrinka.  More challenging contests have unfolded between Nadal and John Isner, whom he would face before the quarterfinals.  Isner extended Nadal to five sets at Roland Garros in 2011 and to two tiebreaks in Cincinnati this summer.  While the world No. 1 aims to chop down that American sequoia, Wawrinka must topple a Canadian redwood in Milos Raonic.  Upset by another giant in Sam Querrey last week, the US Open semifinalist has struggled since that breakthrough.  Raonic, by contrast, has impressed in winning the Bangkok title by defeating Berdych and reaching the Tokyo final.  Nadal might well face three straight opponents of 6’6” or taller as he progresses from Isner to Raonic to Del Potro.  A finalist at Shanghai in its 2009 debut, he should appreciate the relative slowness of the court as he blunts their massive serves.