Rihanna's found a rather comfortable spot heating up the Billboard charts this week. The Bajan beatuy's latest single 'Only Girl in the World,' tops the Digital Songs charts with 249,000 first week downloads marking her eight single to debut on Digital Songs, and her sixth to debut at No. 1, the most reached in each category by an artists since 2005, the year the chart launched. The song jumped 72 spots on the Billboard's Hot 100 chart, and currently sits at No. 3 on the singles chart after premiering three weeks ago.