The songs rank at Nos. 1 and 2 again, respectively, while the former takes over atop Radio Songs and the latter crowns Digital Songs.

Katy Perry's "Dark Horse," featuring Juicy J, scores a fourth week at No. 1 on the Billboard Hot 100, although Pharrell Williams' "Happy" gallops closer with across-the-board-gains as it holds at No. 2.
 
As we do each Wednesday, let's call the race among the songs jockeying for the best positions in the Hot 100's top 10.
 
Perry's ninth Hot 100 No. 1 (and Juicy J's first) continues its command, aided most notably by its coronation (2-1) on the Radio Songs airplay chart, where it gains by 8% to 143 million audience impressions, according to Nielsen BDS. "Horse" marks Perry's seventh Radio Songs No. 1, tying her with Usher for the third-best sum in the chart's 23-year history. Rihanna leads with 12 toppers, followed by Mariah Carey (11). (Read on for more about Carey on this week's Hot 100.)
 
"Horse" crowns the subscription services-based On-Demand Songs chart (3 million U.S. streams, down 1%, according to BDS) for a sixth week and holds at No. 3 on Streaming Songs (which it led three weeks ago) with 6.2 million streams (down 5%). It descends 1-2 after five weeks atop Digital Songs, with a 5% decline to 277,000 downloads sold, according to Nielsen SoundScan.
 

While "Horse" trots into the Hot 100's winner's circle again, Pharrell's "Happy" is fast on the move, holding at No. 2 for a second week with Airplay Gainer honors for a fourth straight week and Digital Gainer kudos for a second frame. "Happy" becomes Williams' first Digital Songs No. 1 (2-1) as a lead artist (and third overall), as it swells by 31% to 329,000 downloads sold. It concurrently storms 10-4 on Radio Songs (109 million, up 27%); 11-7 on Streaming Songs (4.4 million, up 19%); and 11-4 on On-Demand Songs (1.9 million, up 21%).
 
"Happy" also spends a second week at No. 1 on Hot R&B/Hip-Hop Songs.
 
Clearly, the stage is set for another fierce battle for No. 1 on next week's Hot 100. "Horse" drops by 1% in overall points and "Happy" hikes by 28%, with "Horse" now boasting a slim 5% points lead. Last week, "Horse" finished first over "Happy" by a 30% margin.

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Despite Williams' surge and Perry's decline, however, Perry releases the official video for "Horse" tomorrow (Feb. 20), so the clip is sure to boost the song's streaming totals when next week's Hot 100 is compiled, ultimately adding an interesting angle in next week's race for the top spot. (Looking further ahead, Williams will perform "Happy" at the Oscars on March 2. The track is nominated for best original song.)
 
Jason Derulo's "Talk Dirty," featuring 2 Chainz, remains at  No. 3 on the Hot 100, adding the chart's Streaming Gainer nod. The cut pushes 4-2 on Streaming Songs (6.6 million, up 11%) and 17-15 on Radio Songs (67 million, up 13%), while bulleting again at No. 3 on Digital Songs (266,000, up 10%).
 
A Great Big World and Christina Aguilera's "Say Something" also holds at its last-week rank (No. 4), gaining in airplay (93 million, up 1%). As previously reported, the ballad rises 2-1 on Adult Pop Songs, where it's Aguilera's first No. 1 as a lead artist. She'd previously reigned for two weeks in 2011 as a featured artist on Maroon 5's "Moves Like Jagger." (She's placed 17 titles on the tally dating to her first in 1999.) A Great Big World peaked at No. 39 with its sole prior Adult Pop Songs entry, "This Is the New Year," last year.
 
Beyonce and featured artist/husband Jay Z return to the Hot 100's top five (8-5) with "Drunk in Love" (the Rhythmic Songs chart's new No. 1). Two weeks ago, the collab blasted 13-2 after they performed it as the Grammy Awards' opening song (Jan. 26); last week, without the aid of such buzz, it retreated to No. 8. This week, the song sports gains in all metrics: It spends a fourth week at No. 1 on Streaming Songs (7.3 million, up 8%) and rises 14-12 (hitting a new peak) on Radio Songs (84 million, up 12%) and 13-12 on Digital Songs (where it's charted as high as No. 7) with 109,00 downloads sold (up 12%).

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In the bottom half of the Hot 100's top 10, OneRepublic's No. 2-peaking  "Counting Stars" rebounds 7-6 (and drops 1-2 after four weeks atop Radio Songs) and Pitbull's former three-week No. 1 "Timber," featuring Ke$ha, falls 6-7.
 
At Nos. 8-10 on the Hot 100, the top three titles on the Hot Rock Songs chart line up. Bastille's "Pompeii" leads the way, reaching a new Hot 100 highpoint (10-8) and crowning Hot Rock Songs at last in its 40th frame. The song enters the Digital Songs top five (7-5; 146,000, up 11%) and the Radio Songs top 10 (11-8; 94 million, up 13%) and lifts 13-12 on Streaming Songs (3.5 million, up 5%).
 
Lorde's "Team," which reached No. 8 on the Hot 100 four weeks ago, bullets for a second week at No. 9; and Passenger's "Let Her Go" falls from its No. 5 peak to No. 10 (and slides 1-3 on Hot Rock Songs after five weeks at No. 1).
 
Among Hot 100 debuts this week, Tegan and Sara's "Everything Is AWESOME!!!," featuring the Lonely Island, is the top new entry at No. 62. The breakout song from "The LEGO Movie," which has topped the North American box office in its first two weeks (grossing $130 million), roars onto Digital Songs at No. 18 (69,000, up 118%).

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Also notable: Country rapper Buck 22 debuts at No. 80 with "Achy Breaky 2," featuring Billy Ray Cyrus. Powered by its Larry King-assisted video, the song makes over Cyrus' 1992 breakthrough hit "Achy Breaky Heart," which topped Hot Country Songs for five weeks and line-danced to No. 4 on the Hot 100 in 1992 (months before daughter Miley was born that November).
 
Meanwhile, following its release a week ago, Mariah Carey's "You're Mine (Eternal)," the first single from her new album due May 6, enters the Hot 100 at No. 88. Opening sales of 32,000 account for 62% of its chart points. The ballad is Carey's 46th Hot 100 hit, as well as her first non-collaboration/non-cover/non-holiday entry since "Obsessed" became her 27th and most recent top 10 (reaching No. 7) in 2009.
 
Visit Billboard.com tomorrow (Feb. 20), when all rankings, including the Hot 100 in its entirety and Digital Songs, Radio Songs, Streaming Songs and On-Demand Songs, will refresh, as they do each Thursday. The latest charts will also appear in the next issue of Billboard magazine (on sale on Friday, Feb. 21).