(Reuters) - Former U.S. Masters champion Charl Schwartzel came from behind to win the Nanshan China Open by one shot on Sunday after a costly late slip by Northern Ireland's Darren Clarke. Clarke and China's Liang Wenchong started the final round of the $1 million OneAsia Tour event three clear of Schwartzel but the South African shot a brilliant final four-under-par 68 for a nine-under total to pip the pair. It was a first title of the year for Schwartzel, who has now won on the U.S. PGA, European, Sunshine, Asian and OneAsia circuits. "I never thought I was out of it, for any second. ... More...