Before getting knocked out of the top spot on the Billboard Hot 100 singles chart last week by Katy Perry’s “Firework,” Bruno Mars’ “Grenade” was No. 1. This week Mars swaps places with Perry again, sending her to No. 2 and himself right above. At No. 3 is Rihanna’s Drake-assisted “What’s My Name?” Check out the full top 10 after the jump.

Jan. 13, 2011′s Billboard Hot 100 singles top 10:

No. 1 – Bruno Mars, “Grenade”

No. 2 – Katy Perry’s “Firework”

No. 3 – Rihanna,”What’s My Name?”

No. 4 – Ke$ha, “We R Who We R”

No. 5 – P!nk, “Raise Your Glass”

No. 6 – Enrique Iglesias, “Tonight (I’m Loving You)”

No. 7 – Wiz Khalifa – “Black And Yellow”

No. 8 – Black Eyed Peas, “The Time (Dirty Bit)”

No. 9 – Bruno Mars, “Just the Way You Are”

No. 10 – Rihanna, “Only Girl (In the World)”

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