Wawrinka and Murray into last eight, plus a Spanish lefty

By Martyn Herman PARIS (Reuters) - Perennial grand slam title contenders Stan Wawrinka and Andy Murray were joined in the French Open quarter-finals by two unfamiliar faces on Sunday as the Parisian clay continued to turn up unexpected plot lines. It was no surprise to see Swiss title holder Wawrinka beat Viktor Troicki although it took a while for the third seed to subdue the Serb 7-6(5) 6-7(7) 6-3 6-2. Murray's 7-6(9) 6-4 6-3 defeat of John Isner was entirely predictable, even if the second se