Ke$ha continues her reign on the Hot 100 for a sixth straight week with "TiK ToK," surviving a strong challenge from Taylor Swift, who debuts in the runner-up slot with "Today Was a Fairytale."

As reported yesterday,  Swift posts the highest opening-week download sum by a female artist in the history of Nielsen SoundScan tracking (since 2003), as "Today Was A Fairytale" enters Hot Digital Songs at No. 1 with 325,000.

Taylor Swift Swipes Female Downaload Record

Swift is joined by another new entry in the Hot 100's upper tier, as Justin Bieber opens at No. 5 with "Baby," featuring Ludacris. It's the first time the Hot 100 has sported a pair of top five debuts since 2003.

"Baby" is Bieber's first Hot 100 top 10 and previews his sophomore album, tentatively titled "My World Part 2," which is set to be released on March 23. The track also opens at No. 3 on Hot Digital Songs with 199,000 downloads.

Wrapping up the rest of the top 10, Lady Gaga's "Bad Romance' slips 2-3, Young Money holds at No. 4 as the Airplay Gainer (up 13.4 million listener impressions) with "BedRock" and  Iyaz's "Replay" regresses a spot from 5-6 as does "Sexy Chick" from David Guetta featuring Akon (6-7).

"Empire State of Mind" by Jay-Z and Alicia Keys takes the biggest tumble within the top 10 (3-8), landing one spot ahead of Jay's protégé Rihanna, who dips 8-9 with "Hard." Train's "Hey, Soul Sister" slides 7-10.

Black Eyed Peas earn the Hot 100's Digital Gainer tag with "Imma Be" (15-11) as the act moves one step away from a fourth straight top 10 from its album "The E.N.D." "Be" blasts 13-7 on Hot Digital Songs with a 62% bump to 141,000 downloads.

Two tracks from the "Hope for Haiti Now" telethon enter the chart, led by "Stranded (Haiti Mon Amour)" at No. 16. The only original song from the charity event moves 131,000 downloads, more than twice as much as any other track made available for purchase the day following the Jan. 22 airing.

'Hope For Haiti' Album Tops Billboard 200

"Hallelujah" by Justin Timberlake and Matt Morris featuring Charlie Sexton is the other "Hope for Haiti Now" track to make the list, debuting at No. 48 on the Hot 100 with a No. 24 start on Hot Digital Songs (64,000). Surprisingly, this is only the second version of the 1984 Leonard Cohen classic to grace the Hot 100. Kate Voegele spent a single week on the list at No. 68 in the May 31, 2008, issue.

Rihanna debuts with her own contribution to the Haiti relief effort, as her cover of Bob Marley's "Redemption Song" opens at No. 81. The song, performed on the Jan. 20 edition of the "Oprah" show, was immediately made available digitally and shifted 40,000 downloads for the week.