Each year the ATP and WTA tours produce surprising developments, spectacular matches and a few oddities. In 2013, Marion Bartoli's fairytale win at Wimbledon was among one of the more fascinating stories. Bartoli then shocked the tennis world by announcing her retirement just weeks later.
Watching Federer falter became a recurring theme at Grand Slams. Whether Federer switched rackets, fired a coach or tweaked his schedule, his struggles made the news. As we enter 2014, expect more of the same.
Another note-worthy storyline will be who among the up and coming young players will have a breakthrough year. Will it be Sloane Stephens, Simona Halep or Eugeine Bouchard on the women's side? What about Milos Raonic, Jerzy Janowicz or Kei Nishikori on the ATP tour?
There are plenty of heart-warming, compelling stories among the hundreds of players and venues on both tours.
But this list is about what will be the hottest stories in 2014. The list includes Twitter-worthy topics that will yield hashtags and dominate comments sections. These are the tennis storylines that will matter most in 2014.