HOLLYWOOD — As the dust settled on the first week of the fall TV season last week, the big winner was ... UPN?

For most of its existence, Viacom's mini-network has been mocked for its programming, an odd mix of "Star Trek" spinoffs, pro wrestling and cut-rate sitcoms. The business story isn't any better; the network lost so much money — at least $1 billion since starting in 1995 — that senior Viacom executives publicly floated the notion of a shutdown.

Privately, some agents said they wouldn't even bother pitching projects to the network because it paid writers and actors relatively meager rates and its long-term prospects were so unsettled.

So imagine the forehead-slapping in Hollywood suites last week when UPN — with an assist from comic Chris Rock — waltzed to its best premiere week ever, with double-digit growth in total viewers and also among the young adults most sought by advertisers.

The biggest source of UPN's newfound sizzle? "Everybody Hates Chris," the family sitcom that Rock originally developed as a pilot for Fox.

But returning UPN series such as the reality contest "America's Next Top Model" have also hit record highs, according to figures from Nielsen Media Research.

"It's getting the most buzz of any network" this fall, said Stacey Lynn Koerner, executive vice president at ad firm Initiative.

With Rock's involvement — plus a 10-minute sneak peek that drew raves from advertisers in New York in May — "Chris" was expected to open strongly. But its premiere (it airs nationally on Thursday night, but KIKU, which carries UPN shows locally, airs it on O'ahu at 5 p.m. Fridays) received UPN's highest rating ever for a sitcom, with 7.8 million total viewers, handing the season premiere of the NBC comedy "Joey" a humiliating defeat.

Back for its second year, "Joey's" first half-hour drew 7.5 million viewers.

UPN's showing is especially impressive because the network is available only in 90 percent of the United States while NBC is available in virtually every market — and "Joey" was spun off from the network's mega-hit sitcom "Friends." Last season, the NBC comedy averaged 10.2 million total viewers.

Analysts say that with "Chris," Viacom's billion-dollar bet on UPN may finally start paying off. Early next year, Viacom will split its broadcast and radio operations into a separate company from its fast-growing cable networks, including MTV and Nickelodeon. But UPN will remain under the oversight of CBS honcho Leslie Moonves.