Katy Perry posts back-to-back No. 1s on the Billboard Hot 100 as “Teenage Dream” is set to top the chart when it’s released in full tomorrow morning (Sept. 9). She spent six weeks at No. 1 with her last radio single “California Gurls”

The last female artist to post successive No. 1 singles on the chart was Lady Gaga, who took her first two entries, “Just Dance” and “Poker Face,” to the summit in the first half of 2009.

Perry supplants Eminem, who was also enjoying a back-to-back No. 1 run on the Hot 100. “Love the Way You Lie,” featuring Rihanna, led for the past seven weeks (1-2) while his last single “Not Afraid” topped the chart for a week in May. “Teenage” makes its surge to No. 1 thanks in part to a copping a second straight Airplay Gainer award, topping 100 million listener impressions for the first time with a 19% audience gain (7-5 on Hot 100 Airplay), according to Nielsen BDS. The track holds at No. 1 for a second week on Hot Digital Songs with 221,000 (down 15%), according to Nielsen SoundScan.