Field Day’s organizers didn’t need more bad news. For months, they hyped a two-day extravaganza in Calverton, N.Y., with 35 bands. But three days before the event, after authorities refused to grant permits for the Field, planners condensed it to one 12-hour day, shortened the bill to 16 bands, and relocated to Giants Stadium in East Rutherford, N.J. Tickets were refunded, and organizers tried to fill 80,000 seats in 72 hours.

Then, on the designated Day, June 7, it rained. Hard. Still, 20,000 ponchoed fans trudged between the main stage (in the end zone) and the second stage (in the parking lot). Blur and Liz Phair added depth, but headliners Beck, the Beastie Boys, and Radiohead drew the shivering crowd. Then, as the triple-header neared, a dreaded announcement came from the PA.

”Beck…” The crowd roared in anticipation. ”Shhhhhh. Beck took a spill backstage and was taken to the hospital. He won’t be able to perform.” Soon, bewilderment turned to raised fingers, which segued into chants of ”RE-FUND!”

Which is not to say the early acts were without charm. My Morning Jacket — who look like Megadeth but sound like Mercury Rev — wowed the faithful and members of Blur (seen listening backstage). Bright Eyes, who described MMJ’s perfor-mance as ”pretty much the s — -,” gave a typically searing set.

Beth Orton asked roadies to swab the stage (take note, Mr. Hansen) and played a lovely acoustic show that ended, appropriately, with ”I Wish I Never Saw the Sunshine.” As she slicked back her hair and handed off her soaked six-string, Orton sized up the drenched masses: ”You must really love Radiohead.”

And they did. After the Beck-out and the Beasties’ fun but sloppy set, the sky cleared and the Oxford boys made it all worthwhile. In two hours, they moved from melancholic longing (”Subterranean Homesick Alien”) to techno rawk (Hail to the Thief’s ”Myxomatosis”), as frontman Thom Yorke danced like an electrified imp. They proved they are the world’s best rock band and sent a lot of wet people home happy.