Circus produced four singles. "Womanizer" debuted at number 96 on the US Billboard Hot 100 and ascended to the summit in its second week, registering the largest leap on the chart at the time. It became Spears' best-selling single in the country since her debut "...Baby One More Time" (1998). "Circus" debuted and peaked at number three on the Billboard Hot 100; consequently, Circus became Spears' first album since her debut ...Baby One More Time (1999) to have two top-ten singles. Subsequent singles "If U Seek Amy" and "Radar" peaked at numbers 19 and 88 on the Billboard Hot 100, respectively. To further promote the album, Spears embarked on the world tour The Circus Starring Britney Spears (2009).