Easy as it is to assemble a list of significant Australian Open story lines — from Rafael Nadal's bid for a men's-record 21st Grand Slam singles trophy to Serena Williams' try for her 24th, from Novak Djokovic's attempt to win a third consecutive title at Melbourne Park to Sofia Kenin's defense of her first major championship, and so on — nothing hangs over the upcoming two weeks quite like questions involving the coronavirus. (More Tennis News)