No offense to Jingle Ball but there is no better measuring stick for success than a Saturday Night Live musical guest spot. A night after performing to tens of thousands at Z100’s annual pop radio celebration at Madison Square Garden, Charli XCX had an appointment in front of millions thanks to SNL, who named the 22-year-old British hitmaker as their musical guest days before she releases her breakthrough album Sucker. If her SNL “Boom Clap” was a nod to the Eighties, then “Break the Rules” was her ode to the Nineties, and Charli dressed the part. (The song’s music video also pays homage to Nineties dark comedies like The Craft and Jawbreaker.) This “Break The Rules” wasn’t as dynamic as the lollipop-smashing teenage riot rendition that Charli brought to the American Music Awards – the Christmas-lighted SNL stage disrupts the mood – but both performances were enough to let people know that Charli XCX is a force to be reckoned with in 2015.