Rosberg leads on 'tricky' day for Hamilton

By Alan Baldwin BARCELONA (Reuters) - Formula One championship leader Nico Rosberg set the pace in Friday practice for a Spanish Grand Prix that could see the Mercedes driver celebrate his eighth win in a row. While the German had no problems to report, his three-times world champion team mate and closest rival Lewis Hamilton complained about his car's handling after ending third-fastest. Rosberg, who could become only the third driver to win the first five races of a season on Sunday, after com