A month before it officially starts, the new fall television season has its first potential hit on its hands.

Fox jumped the gun Sunday with its critically acclaimed comedy, "That '70s Show," and it finished 21st in Nielsen Media Research's rankings of the week's prime-time shows. More impressive, it was the week's most-watched program among the 18-49 age group coveted by advertisers and even outrated the season premiere of Fox's long-running hit "The Simpsons.""That '70s Show" is about teens growing up in Wisconsin in 1976.

The early start didn't help Fox's second new Sunday night comedy, "Holding the Baby." The show about a single father finished a dismal 86th among 116 prime-time shows, Nielsen said.

For the week, CBS's 6.9 rating and 12 share narrowly edged NBC's 6.8/12 share for first place. ABC was heartened by its 6.4/12, the closest it has been to NBC in five months. Fox had a 4.8/9 share, the WB had a 2.5/4 and UPN was at 1.7/3, Nielsen said.

The week's biggest attraction was President Clinton's Monday-night speech admitting to a relationship with Monica Lewinsky. It drew an estimated 67.6 million viewers on several networks. By contrast, the week's highest-rated scheduled show, "60 Minutes," had an audience of 16.5 million.

Post-speech analyses on NBC and CBS were ranked among the week's top 10 shows.

In the evening news competition, NBC's "Nightly News" had a big win in a big news week. Its 8.2 rating and 18 share topped ABC's "World News Tonight," which had a 7.5/17. The "CBS Evening News" had a 7.2/16.

A rating point represents 980,000 households, or 1 percent of the nation's estimated 98 million TV homes. Share is the percentage of in-use televisions tuned to a given show.

For the week of August 17-23, the top 10 shows, their networks and ratings were: 1. "60 Minutes," CBS, 11.8; 2. "Presidential Apology Analysis," NBC, 10.9; 3. "Dateline NBC-Tuesday," NBC, 10.4; 4. (tie) "Just Shoot Me," NBC, and "Seinfeld," NBC, 9.7; 6. "PrimeTime Live," ABC, 9.4; 7. "ER," NBC, 9.3; 8."Friends," NBC, 9.2; 9. "CBS News Special Report: Analysis," CBS, 8.8; 10. "20/20-Friday," ABC, 8.7.

11. (tie) "Nightline in Primetime," ABC, and "Touched by an Angel," CBS, 8.3; 13. "Dateline NBC-Monday," NBC, 8.2; 14. (tie) "CBS Sunday Movie: Nothing Lasts Forever, Part 1," and "Whose Line is it Anyway?," ABC, 8.1; 16. (tie) "The Drew Carey Show," ABC, "Home Improvement," ABC, and "NFL Pre-season Football Special: Dallas vs. New England," ABC, 7.9; 19. (tie) "Guinness World Records: Prime Time," Fox, and "NBC Sunday Movie: A Kiss So Deadly," 7.8.