Rihanna has scored a third week at the top of the U.S. pop charts with her 'Rude Boy'.

The track holds off B.o.B.'s 'Nothin' On You' at two and a charge from Train, who gain four spots at three with 'Hey, Soul Sister'.

Former chart topper 'Need You Now' by Lady Antebellum and Lady Gaga and Beyonce's 'Telephone' round out the new top five.

Justin Bieber scores the highest debut on the Hot 100 for a second successive week - his Eenie Meenie collaboration with Sean Kingston enters the countdown at 30.