Eilish earns her first leader, ending an unprecedented nine-week wait at No. 2.

Billie Eilish earns her first No. 1 on the Billboard Hot 100, as "Bad Guy" rises from No. 2. The song reigns after spending nine total weeks at the runner-up spot, the most for any title before reaching the summit in the Hot 100's history.

"Bad Guy" additionally claims the honor of conquering the longest-leading Hot 100 No. 1 all-time, as it halts the 19-week domination of Lil Nas X's "Old Town Road," featuring Billy Ray Cyrus.

Let's run down the top 10 of the Hot 100 (dated Aug. 24), which blends all-genre U.S. streaming, radio airplay and digital sales data. All charts will update on Billboard.com tomorrow (Aug. 20).

"Bad Guy," released on Darkroom/Interscope Records and written by Eilish and Finneas O'Connell (her brother), who solely produced it, becomes the 1,087th No. 1 in the Hot 100's 61-year history.

The song rises 4-3 on the Streaming Songs chart, up 10% to 39.1 million U.S. streams in the week ending Aug. 15, according to Nielsen Music, and 7-6 on Digital Song Sales, up 11% to 20,000 sold in the same span; it was aided on the last day of the streaming and sales tracking period by the arrival of a new vertical video, as well as a cassette single available only through Eilish's official website. On the Radio Songs chart, the track drops 3-6, down 3% to 93 million audience impressions in the week ending Aug. 18.

No. 1 after record 9 weeks waiting at No. 2: "Bad Guy" tops the Hot 100 after nine nonconsecutive weeks at No. 2, the most weeks spent at the runner-up spot before leading the list. It passes The Weeknd's "Starboy," Justin Bieber's "Sorry" and OutKast's "The Way You Move" (featuring Sleepy Brown), each of which ruled after eight-week waits at No. 2 before leading at last in 2017, 2016 and 2004, respectively.

Alt back at No. 1: "Bad Guy" tallies a second week atop the Pop Songs airplay chart (thanks in part during its run to a remix with Bieber), after leading the Alternative Songs airplay survey for two weeks. It's the first Alternative Songs No. 1 to top the Hot 100 since Lorde's "Royals," which ruled the Hot 100 for nine weeks beginning in October 2013, after leading Alternative Songs for seven weeks.

21st century leader: Born Dec. 18, 2001, Eilish is the first artist born in the 2000s to top the Hot 100. Lil Nas X previously came closest to the distinction, having been born April 9, 1999. Eilish, 17, is the youngest artist to reign since Lorde, who was 16 when "Royals" began its nine-week command.

No. 1 album & song: "Bad Guy" is from Eilish's LP When We All Fall Asleep, Where Do We Go?, which debuted at No. 1 on the April 13-dated Billboard 200 albums chart and has led the list for three total weeks. She first reached a Billboard survey in October 2017, while, the next month, her 2017 set Dont Smile at Me entered the Billboard 200 at No. 185; it has since reached No. 14 (and ranked in the chart's top 40 every week of 2019; When We All Fall Asleep has placed in the top five in each of its first 20 weeks).

"I'm in the good old days right now," Eilish marveled in a May Billboard cover story.

Shawn Mendes and Camila Cabello climb 3-2 on the Hot 100 with "Señorita," as the duet returns to its peak rank, first reached upon its debut in nearly July. The collaboration surges 7-3 on Radio Songs (96.1 million, up 7%) and rises 5-4 on both Streaming Songs (36.2 million, up 4%) and Digital Song Sales (23,000 downloads sold, up 4%).

Lil Nas X's "Old Town Road," featuring Cyrus, drops to No. 3 on the Hot 100 after its record 19 weeks at No. 1. Still, it becomes the first single to top Streaming Songs for 20 weeks (53.1 million, down 10%). It rules Digital Song Sales for a 16th week (26,000, down 23%), moving to within one week of the record: Luis Fonsi and Daddy Yankee's "Despacito," featuring Bieber, dominated for 17 weeks in 2017. On Radio Songs, "Road" falls 21-28 (34.2 million, down 13%).

"Road" additionally tops the Hot R&B/Hip-Hop Songs and Hot Rap Songs charts for a record-extending 20th week each and the Songs of the Summer chart for a 12th frame, having led the list each week since its annual return after Memorial Day.

("Road," as of this week, kept a record six songs peaking at No. 2 during its No. 1 run, with "Bad Guy" having now risen from a No. 2 high to the summit. The titles to reach No. 2 below "Road," listed chronologically by peak date: Post Malone's "Wow."; Taylor Swift's "ME!," featuring Brendon Urie; Mendes' "If I Can't Have You"; Ed Sheeran and Bieber's "I Don't Care"; Swift's "You Need to Calm Down"; and Mendes and Cabello's "Señorita.")

Lizzo's "Truth Hurts" is steady at its No. 4 Hot 100 high and Khalid's No. 3-peaking "Talk" keeps at No. 5, while ruling Radio Songs for a 10th week (123.6 million, down 5%) and Hot R&B Songs for a 17th frame.

Chris Brown's "No Guidance," featuring Drake, repeats at its No. 6 Hot 100 peak and Sheeran and Bieber's "Care" is stationary at No. 7.

Lil Tecca's "Ran$om" reaches a new No. 8 Hot 100 high, rising from No. 10 with top Streaming Gainer honors, as it pushes 3-2 on Streaming Songs (43.3 million, up 18%); Post Malone's "Goodbyes," featuring Young Thug, holds at No. 9 on the Hot 100, after debuting at its No. 3 best; and, rounding out the top 10, Mendes' "If I Can't Have You" returns to the tier (11-10).

Find out more Hot 100 news on Billboard.com this week, and, for all chart news, you can listen (and subscribe) to Billboard's Chart Beat Podcast and Pop Shop Podcast and follow @billboard and @billboardcharts on both Twitter and Instagram. And again, be sure to visit Billboard.com tomorrow (Aug. 20), when all charts, including the Hot 100 in its entirety, will refresh. The next issue of Billboard magazine is on sale Friday (Aug. 23).