Three decades ago, in an interview with chart-trivia master Fred Bronson for his Billboard Book of Number 1 Hits, Blondie lead singer Debbie Harry said the following about 1981’s “Rapture”—the song with the rap about the man from Mars who’s eatin’ cars, and the first Hot 100 No. 1 song to feature rapping.

“It took some getting used to for the guys [in the band],” Harry said. “They really weren’t solidly behind rap music at the time. It was very underground … They thought it might have been a little too much.”

Discussing what, if anything, she would go back and change about her performance, Harry added: “I think I would do the rap a little, what I would call tighter, more precise. To me it’s a little bit off the beat. I only did one take on it and that was it. So if I were to do it again, I would have done a couple more takes.”

Much as I hate to disagree with Harry about her art—she and Blondie co-leader Chris Stein followed their muse to four stellar No. 1 songs, each in a vastly different style—she’s at least a little bit wrong on both counts. First, the other members of Blondie were probably wise to be wary about attempting rap; besides imperiling their rock bona fides, it may have felt like one cultural appropriation too far. And second, the slackness of Harry’s rap may be the best thing about “Rapture.” Its shambling quality is true to Harry’s urban-white-girl persona, saving it from the kind of appropriation the rest of the band likely feared. Thank heavens she didn’t try another take.

Thirty-three years later, one white lady who doesn’t hesitate to appropriate is Iggy Azalea. The 23-year-old Australian model and rapper possesses the new No. 1 song on the Hot 100, “Fancy” featuring Charli XCX.

For Azalea, born Amethyst Amelia Kelly in New South Wales, there’s no second-guessing or wishing for another take. Iggy thinks she’s awesome, and she’s here to tell you: “Honest, the truth is—my flow, retarded; each beat, dear, departed.” Having relocated to Miami at age 16, she adopted the argot and flow of an African-American from the Dirty South; hip-hop academic and critic Oliver Wang calls it “a hat trick of appropriation: not American, not black, not southern.” As if leaning into the criticism, Iggy unleashes the bravado within “Fancy’s” first 10 seconds, in the song’s most memorable and oft-quoted rhyme: “First things first: I’m the realest,” a statement laced with either unwitting irony or sardonic self-commentary—probably both.

Azalea’s peacocking and overcompensation make a kind of sense, inasmuch as very few female rappers of any race have ever topped Billboard’s premier song chart. Besides Harry, who doesn’t even rap all the way through “Rapture,” there’s Lauryn Hill, who made it to No. 1 in 1998 with “Doo Wop (That Thing),” her singing-and-rapping take on ’60s girl-group soul. Three years later, rapper Lil Kim shared credit on a No. 1, the 2001 remake of Labelle’s “Lady Marmalade,” a four-diva pile-up that also featured Christina Aguilera, Mya, and P!nk. And, unless you consider Ke$ha a rapper—a valid but not-uncontroversial opinion held by, among others, the New York Times’ Jon Caramanica—that’s it for lead female rappers at No. 1, until Azalea this week. (Among many injustices, rap godmothers Salt-n-Pepa peaked at No. 3 on the Hot 100, and hip-hop innovator Missy Elliott has never gotten past No. 2.)

So let’s give it up for the ladies who rap—even if Azalea’s play-acting has been called everything from minstrelsy to, more charitably, rap’s greatest drag performance. I have written my share in the past six months about the charts, race, and how the digital era has given a lift to hegemonic pop culture; we needn’t go there again. Besides, the title of this series isn’t “Why is cultural appropriation so profitable?” (Short answer: It always has been.) It’s “Why is this song No. 1?” And it has to be said that “Fancy” is crafted like a Swiss watch.

As a pop-radio dominator, “Fancy” has two big things going for it: tight production and a great supporting performer. Rhythmically the song is electro-hop, powered not by a traditional rap breakbeat but by a rubbery synth bounce. That sound is indebted to early-’80s electro-rap pioneer Afrika Bambaataa, Nu Shooz’s 1986 pop&B classic “I Can’t Wait,” and late-’80s female-rap trio JJ Fad. “Fancy’s” London-based production team The Invisible Men, working with co-producer Kurtis “The Arcade” McKenzie, have reduced the song’s sonic footprint to little more than that digital pulse and a recurring skitter-step beat, which owes more than a little to the 2004 smash “Tipsy” by J-Kwon.

But of all the talents swirling around “Fancy,” the song’s true MVP is its featured performer, Charlotte Aitchison, aka Charli XCX, possessor of the Gwen Stefani–like voice that coos the song’s sticky hook. If her voice sounds familiar, it’s probably because you spent last summer strutting to it, too: The pavement-crusher “I Love It,” credited to Swedish duo Icona Pop featuring Charli XCX (a 2012 single that took a full year to emerge), was largely Aitchison’s confection. So “Fancy” makes this the second straight year the British singer-songwriter has powered a monster summer jam credited to others that sprang in large part from her head. Further evidence of Charli’s skill can be found on her critically acclaimed 2013 album True Romance, packed with chewy hooks that have pop fans falling over themselves to praise her. (Could someone please get this lady a hit of her own now, please?)

Compared to Charli’s monster hook, Azalea’s rapping is the track’s weaker sister. Iggy may be a more confident rapper than Debbie Harry in 1981, but she also sounds like she’s trying really hard. But what’s grating over the length of Azalea’s album The New Classic is more charming on a supple pop single; her effortfulness kind of works here. Having trained herself to rap in a cadence vastly different from her native speaking voice, Iggy’s comes off brash but studied, and she resembles no one so much as her mentor, Atlanta rapper T.I. Listen to the way her tone rises on the line “You should want a bad bitch like this, hah?”—a clear homage to T.I.’s singsongy, conversational tone on smashes like “Live Your Life” or his rap bridge on Justin Timberlake’s classic “My Love.” They say that good artists copy and great artists steal. Azalea is, at her best, a competent copycat, and she’s unafraid to insert herself into the lineage of rap’s greats. Her line about a rooftop in ’88 isn’t nostalgia for a time before Azalea was born: It’s an allusion to a rhyme by Nas.

But forget the ’80s and the ’00s: Iggy is, to borrow a term from Charli’s other big hit, “a ’90s bitch.” That’s confirmed by the song’s YouTube-dominating music video, an homage to Clueless, the 1995 Alicia Silverstone comedy. Billboard reports that the video was a linchpin in the song’s climb to No. 1, having been viewed some 60 million times since its March debut. With the 20-year nostalgia cycle in full effect, Amy Heckerling’s teen-cinema masterwork was right on schedule for homage, though it’s hard to see what Azalea brings to the party other than recreating some the film’s best scenes and looking cute in Cher Horowitz’s yellow plaid. If you squint pretty hard, you can see the video saying something about how young people—suburban teens or arriviste rappers—construct themselves; though, honestly, that may be giving a clip likely dreamed up in a marketing meeting (“Is this, like, a Noxzema commercial or what?!”) more credit than it deserves.

Between the smash music video and a sales-juicing TV performance in mid-May on the Billboard Music Awards, “Fancy” got its momentum to reach No. 1. During that same BBMAs performance, Azalea joined big-lunged pop star Ariana Grande for a performance of “Problem,” the Ariana-fronted, Iggy-supported single that’s currently No. 2 on the Hot 100. These songs’ dual command of the chart has led to online chatter about just how Zeitgeist-dominant Azalea is right now.

As if stirring the pot, Billboard noted that Azalea is the first act to capture the chart’s top two positions with her first two Hot 100 hits since the Beatles. Any Billboard feat involving a modern pop act and the phrase “since the Beatles” is guaranteed to rile up chart nerds, but the record is a footnote and an accident—for both acts. It’s no proud statistic for the Fab Four, who didn’t chart in America until early 1964 only because the band’s U.S. label refused to promote its records here sooner; once Beatlemania reached American shores, a flood of singles on multiple labels rushed the Hot 100, sending “I Want to Hold Your Hand” and “She Loves You” to the top two positions even though other Beatles singles should have charted earlier. And Azalea should have scored lower-charting hits as far back as 2011, except that complicated label politics, and a slew of tracks recorded under prior contracts but withheld from promotion, essentially kept her off the radio more than two years, before Island Records finally sent her into the studio to record her “official” debut.

The other act Azalea’s being freely compared to this summer, thanks to her hit duopoly, is Summer 2013 dominator Pharrell Williams. With “Fancy” and “Problem” set to duke it out for the Hot 100 penthouse over many weeks, much the way last year’s two Pharrell-supported hits held down Nos. 1 and 2 for more than a month, Azalea is looking like Summer 2014’s special sauce. But Azalea isn’t a supporting performer on “Fancy,” she’s the lead. And anyway she doesn’t have the decades of history Pharrell built as a writer-producer—if anyone right now deserves the X-factor designation, it’s Charli XCX. About the only thing Pharrell and Iggy have in common is taking a turn as America’s shiny new object after hiding in plain sight.

Ultimately, the success of “Fancy” is owed largely to timing, which is the dark art of major-label pop promotion. Knowing when a style—in this case, ’80s/’90s–referencing electro-rap—is ascendant is a skill in itself, and after years of Azalea scoring more headlines than hits, her team managed to make her seem new again. Whether “Fancy” signals longevity for her is another matter. For Blondie in 1981, “Rapture” came at the end of a great two-year run as New Wave’s biggest band; neither the group nor Debbie Harry came anywhere near Billboard’s Top 10 again. Shambling rap may have closed their career, but now it’s 2014, not 1981. If Iggy Azalea truly is “the realest,” a career as hip-hop’s leading lady is now hers to lose.

Previously in Why Is This Song No. 1?

John Legend’s “All of Me”

Pharrell’s “Happy”

Katy Perry’s “Dark Horse”

Pitbull and Ke$ha’s “Timber”

Eminem’s “The Monster”