"Rockstar 101" was released before "Love the Way You Lie," so if "Only Girl" hit number one, then she has two back-to-back numbers ones according to Billboard.
Actually, I'm pretty sure by Billboard's standards, if Only Girl had reached #1, it wouldn't be back to back. If I'm not mistaken, Rockstar 101 first appeared on the charts after LTWYL first did. That's why they consider Taio Cruz to be one of the only males this year to send his debut single to #1, because none of his other previous singles charted in the US. Billboard goes by charting date, not release.
