Three months after Radiohead shocked the system with a “pay what you want” digital model for “In Rainbows,” the album hit No. 1 in its first week of availability on compact disc.

“In Rainbows” received a standard release by TBD/ATO on New Year’s Day as a physical product and a download, selling 122,000 copies, according to Nielsen Soundscan. The week earlier, 9,000 were sold ahead of the street date, allowing it to debut at No. 152.

While it was available via Radiohead’s website from October to early December, an estimated 2.4 million copies were downloaded. The band has never released sales figures for the MP3 version nor an expanded version that was sold via mail order for $80.

“In Rainbows” squeaked past Alicia Keys’ “As I Am,” which was the only other disc to hit six figures, selling 112,000. Last week’s No. 1, Mary J. Blige’s “Growing Pains,” dropped 56%, selling 89,000 and hitting No. 3.

The digital strategy for the soundtrack to “Juno” also seems to have worked. Rhino released the compilation album online only last week, selling 38,000 copies to hit No. 8. CDs went on sale Tuesday, and the album appears in position to take over the top slot next week, most likely topping 100,000 in sales.

The next highest debut belonged to another compilation, “Grammy Awards: 50th Anniversary Collection” (Shout Factory!), which sold 16,000 to hit No. 54.

Among significant gainers were the “Alvin and the Chipmunks” soundtrack (Razor & Tie), selling 33,000 to rise 20 slots to No. 13, and Sara Bareilles’ “Little Voice,” which saw sales of 23,000 and rose 14 slots to No. 31. Blowout pricing at Target moved Elliott Yamin’s holiday disc “Sounds of the Season”: It sold 23,000 copies and moved up 91 spaces to No. 32.

Speaking of the year-end holidays, Josh Groban’s “Noel” did find nearly 15,000 people preparing for Christmas 2008, as it came in at No. 58.