Robert Rock of England took the clubhouse lead Friday in the storm-battered second round of the Joburg Open as US Masters champion Charl Schwartzel continued to struggle. Rock carded a 67 over the easier west layout for an 11-under-par total of 132 before thunder and lightning halted play with only half the 210-field finishing their rounds in the two-course European Tour event. The 34-year Englishman is one stroke ahead of South Africans Jbe\' Kruger and Branden Grace with compatriot Michiel Bothma a shot futher back after all had a 66 at Royal Johannesburg and Kensington Golf Club. Schwartzel trails Rock by eight after a 68 and his hopes are slim of joining Ernie Els, Nick Faldo, Colin Montgomerie, Tiger Woods and Ian Woosnam in the record books by winning the same European Tour event three consecutive times. Rock, a 34-year-old whose lone European Tour triumph came in the Italian Open last season, had a mixed round with one eagle, four birdies and two eagles over the less demanding par-71 west course. \"I played better in the first round over the harder course, but still managed to compile a decent score which is what matters,\" said the golfer ranked 123 in the world. The overnight leaders saw little second-round action with Irishman Damien McGrane one over after three holes and Englishman Jamie Elson yet to start his east-course journey.