'Uptown Funk' or 'See You Again': Which Will Be No. 1 on Next Week's Hot 100?

Hutton Supancic/Getty Images for SXSW
Wiz Khalifa performs onstage at the Atlantic Urban showcase during the 2015 SXSW Music, Film + Interactive Festival at Brazos Hall on March 18, 2015 in Austin, Texas. 

A battle is brewing between Mark Ronson & Bruno Mars' "Funk," which could notch a 15th week on top, and Wiz Khalifa & Charlie Puth's "Again," which could surge to the summit from No. 10.

Will Mark Ronson's "Uptown Funk!," featuring Bruno Mars, spend a 15th week at No. 1 on the Billboard Hot 100? Or will Wiz Khalifa's Furious 7 soundtrack single "See You Again," featuring Charlie Puth, dethrone it by blasting to the top from No. 10?

Ahead of the unveiling of the Hot 100 (dated April 25) on Billboard.com next Wednesday, April 15, when the top 10 will be revealed (with the chart to update in full the following day), the race, as of now, looks close, with "Again" trending to wind up the leader. The Hot 100 measures songs' sales, radio airplay and streaming data.

The stakes are high, historically: If "Funk" logs a 15th week at No. 1, it would pass six other singles in the runner-up spot that have also each led for 14 weeks and move to within one week of the all-time record: Mariah Carey and Boyz II Men's "One Sweet Day" reigned for 16 weeks in 1995-96.

'Uptown Funk' Ties for Second-Longest-Leading Hot 100 No. 1 of All Time

According to the latest industry projections, however, "Again" is posing a serious threat to the rule of "Funk," as the former could sell more than 400,000 downloads in the week ending Sunday (April 12). Helping fuel sales: continued high interest in Furious 7 at the box office, as the action film has soared past $500 million in worldwide receipts in its first seven days.

The April 6 release of the song's official video, a touching clip that pays tribute to late Furious franchise star Paul Walker, has also helped ignite sales, and the clip's chart impact is twofold: in addition to pushing sales gains, its streaming numbers, which include clicks for the video, are expected to rocket on next week's charts.

Airplay for "Again" is also rising, although to nowhere near its expected sales and streaming levels next week. The track is nearing the 50-position Radio Songs chart.

On the current Hot 100 (dated April 18), "Again" ranks at No. 10, having bounded from No. 84 after Furious 7 premiered in theaters on April 3. It sports a 42-1 vault on the Digital Songs chart with a 488 percent gain to 168,000 downloads sold, according to Nielsen Music. On Streaming Songs, it's new at No. 26 with 4.1 million U.S. streams (up 259 percent).

'Furious 7' Soundtrack Heading for No. 1 on Billboard 200 Chart

Will those projected next-week figures for "Again" be enough for it to topple "Funk"? Barring any sudden surges, "Funk" will likely continue its steady declines in sales, airplay and streams. On the charts dated April 18, "Funk" ranks at No. 1 on Radio Songs (159 million, down 5 percent) and Streaming Songs (15.8 million, down 3 percent) and No. 2 on Digital Songs (163,000, down 1 percent).

With all numbers crunched, it's shaping up to an exciting finish as to who'll rule next week's Hot 100. Check Billboard.com Wednesday, April 15, to find out the winner, and whether "Funk" will continue its historically rare reign … or if "Again" will take over as, after a long wait by all challengers, the Hot 100's new No. 1 song.

--Additional reporting by Keith Caulfield and Silvio Pietroluongo