fun.'s "We Are Young," feat. Janelle Monae, tops the Billboard Hot 100 songs chart for a fifth week, just holding off Justin Bieber's "Boyfriend," which debuts at No. 2 with the second-highest-ever debut digital sales week at 521,000 first-week downloads, according to Nielsen SoundScan.

"Boyfriend" likewise logs an impressive first week of airplay, debuting at No. 24 on the Radio Songs chart with 40 million audience impressions, according to Nielsen BDS. With its No. 2 start, Bieber notches his highest Hot 100 placement. He had previously ranked as high as No. 5 when "Baby" debuted (and peaked) at No. 5 the week of Feb. 6, 2010.

A notable factor in the chart battle between "Boyfriend" and "Young" is the latter song's upper hand in streaming. "Young" remains atop the On-Demand Songs chart with 1.18 million on-demand streams (flat from last week) in the chart's tracking week, according to BDS.

Gotye's "Somebody That I Used to Know," feat. Kimbra, rises 4-3. The collaboration, which tops Alternative Songs for a seventh consecutive week, gained 17% to 244,000 downloads sold. It advances 20-16 on Radio Songs (52 million, up 23%) and remains at No. 2 on On-Demand Songs (961,000, up 10%).

Rounding out the Hot 100 are U.K. boy band The Wanted, slipping 3-4 with "Glad You Came," and Kelly Clarkson's "Stronger."

Read the Variance cover story on Gotye.

Read the Variance cover story on fun.