2. Stanislas Wawrinka: He had the best year of his career in 2013. The reason he lands at No. 2 is that, despite strong showings in Grand Slams, Wawrinka always seems a few unforced errors away from making it to a final. Wawrinka needs to show that he can weather the pressure in big matches against the big guns. Putting away the likes of Tomas Berdych is no longer enough. His win over Murray at the U.S. Open raised expectations. Now he has to prove he is ready to take the next step.