Motor racing-Rosberg again denies Hamilton his 50th pole

SOCHI, Russia, Oct 10 (Reuters) - Germany's Nico Rosberg took pole position for the Russian Formula One Grand Prix on Saturday with Mercedes team mate Lewis Hamilton joining his title rival on the front row. The top grid position was Rosberg's third of the season with championship leader Hamilton denied his 50th career pole for the third race in succession. The qualifying was still a perfect result for Mercedes and kept the team on course to clinch their second successive constructors' title this weekend. Finland's Valtteri Bottas qualified third for Mercedes-powered Williams with Ferrari's Sebastian Vettel and Kimi Raikkonen fourth and fifth. (Reporting by Alan Baldwin, editing by Ed Osmond)