Prague Challenger: India's Sumit Nagal loses to Stanislas Wawrinka in QF

India's Sumit Nagal lost to world number 17 and three-time Grand Slam winner Stanislas Wawrinka from Switzerland in the quarterfinal of the Prague Challenger tennis tournament today.   Nagal made an emphatic start, winning the first set 6-2 in 36 minutes. In the second set, however, Wawrinka fought back to claim the set 6-0. The Swiss continued to assert his domination, winning the match 2-6, 6-0, 6-1.   The 22-year-old Indian, who is ranked 127 in the world and seeded sixth in the tour...