Motor racing-Hamilton takes fourth pole in a row

MANAMA, April 18 (Reuters) - Formula One world champion Lewis Hamilton continued his season's sweep of qualifying at the Bahrain Grand Prix on Saturday with his fourth successive pole position for Mercedes. The Briton was joined on the front row by Ferrari's Sebastian Vettel, with fellow German Nico Rosberg managing only third for Mercedes. The pole position was a 15th in a row for champions Mercedes and Hamilton's first in Bahrain, a race he won from second place last year. Ferrari's Kimi Raikkonen qualified fourth. (Reporting by Alan Baldwin, editing by Mark Meadows)