Fall usually brings closures, codas, endings rather than beginnings.  This week, however, fall brings the renewal of a marquee ATP rivalry between Roger Federer and Novak Djokovic, aligned to square off in a semifinal at the Paris Masters 1000 tournament.

Between 2009 and 2012, these two pillars of the ATP met five times each year in semifinals or finals of the most prestigious tournaments in the sport.  The Serb and the Swiss collided at every major, two editions of the year-end championships, and six of the nine Masters 1000 events.  Yet they have not met in 2013, on any stage large or small.

Federer bears most of the responsibility for the disappearance of this mega-rivalry, the most bitter of all those among the Big Four.  It is no secret that sparks have spurted between the two men and their entourages in the past, friction perhaps fueled by the clash in personalities between the smooth Swiss and the pugnacious Serb.  While respect has defined most of his interactions with nemesis Rafael Nadal, Federer appeared to resent the incursions of Djokovic upon his territory at the top.  For his part, Djokovic appeared to gain particular satisfaction from slaying the man who ruled the ATP for so long.  Fans might recall Djokovic’s mother, Dijana, proclaiming that “the king is dead” after the 2008 Australian Open, or Federer hurling a curt “shut up” at Djokovic’s family in Monte Carlo a few months later.

But Federer rules the ATP no longer, able to reach the final at only one Masters 1000 tournament this year (Rome) and dismissed by the quarterfinals at each of the last three majors.  This week marks only his second semifinal at an elite tournament since the Australian Open, whereas Djokovic has sustained superior consistency.  Never losing before the semifinal at any major, he also has collected two Masters 1000 titles and reached the semifinals of two others.  Still, Djokovic has not quite matched a metronome this year.  He has fallen to Tommy Haas, Grigor Dimitrov, and John Isner at Masters 1000 tournaments, and to Tomas Berdych in the quarterfinals of Rome. 

Both men enter this semifinal infused with momentum after defeating top-eight opponents on Friday.  For Federer, a three-set victory over Juan Martin Del Potro avenged a loss last week at his home tournament in Basel and marked his first victory of the season over a top-five foe.  Djokovic’s win over Stanislas Wawrinka did not surprise, for he has claimed 12 straight encounters with the Swiss No. 2.  Wawrinka had extended him to five sets at both hard-court majors this year, though, so the Serb’s dominance still impressed in a more muted way.

Historically, the Federer-Djokovic rivalry has revolved around the battle between Federer’s serve and Djokovic’s return.  Each of those weapons ranks among the greatest versions of those strokes that the game ever has seen.  On an fast indoor hard court like Paris, the serve should hold an advantage in that matchup, but Djokovic won a high-quality indoor battle with Federer at the year-end championships last year.  The baseline balance of power between the two men has shifted somewhat during Djokovic’s rise and Federer’s decline.  While the Serb always has held the edge in backhand-to-backhand rallies with his two-hander able to overpower his rival’s one-hander, the Swiss initially dictated many of the forehand-to-forehand exchanges.  During recent years, Federer’s advantage in that area has waned as his forehand has grown less consistent and Djokovic’s forehand more lethal.

The mental component looms especially large when two men have grown so familiar with each other’s games.  Less lies at stake for both men than in many of their previous encounters. Federer has qualified already for the World Tour Finals, while the year-end No. 1 ranking essentially lies out of reach for the Serb, considering current No. 1 Rafael Nadal’s steady results.  Moreover, perceptions of Djokovic’s outstanding but frustrating season at the majors would not change based on what happens in Paris.  Djokovic may rank a second Davis Cup title foremost among his goals for the remainder of the season, as he did in 2010.  And Federer cannot salvage a season of decline at majors by snatching a late fall title or two.  Only a resurgence in 2014 can erase the epitaph that some already have written on his career. 

All the same, any collision between two members of the original Big Four (Djokovic, Nadal, Federer, and Andy Murray) merits a heightened level of scrutiny.  Known for chaotic upsets and unexpected, one-hit champions, Paris will gain credibility from featuring the latest edition of Djokovic-Federer.  No man outside the top 10 reached the quarterfinals there this year, the first such Masters 1000 event to produce such a lineup since the Rogers Cup in 2009.  A final that pits either of these men against Nadal would end the ATP regular season in style. 

One man must lose, but no fan will.

Djokovic, 6-4 2-6 6-4