A roundup of the week Sept. 11-17

BOXING—MUHAMMAD ALI regained the WBA heavyweight championship from Leon Spinks, winning a unanimous 15-round decision before a crowd of 70,000 in the New Orleans Superdome. On the same card, 22-year-old MIKE ROSSMAN of Turnersville, N.J. won the WBA light-heavyweight title from Victor Galindez of Argentina on a 13th-round TKO; DANNY (Little Red) LOPEZ of Los Angeles retained his WBC featherweight title with a second-round KO of Juan Malvarez of Argentina; and JORGE LUJAN of Panama retained the WBA bantamweight championship on a 15-round decision over Alberto Davila of Mexico (page 16).

CHESS—Challenger Viktor Korchnoi won his second game of the world championship in Baguio City, Philippines, forcing world champion Anatoly Karpov to resign on the 60th move of the 21st game. Karpov still leads the series with four victories. There have been 17 draws.

EQUESTRIAN EVENTS—BRUCE DAVIDSON won the individual title at the World Three-Day Event Championships for the second time. CANADA, which scored 397.6 points, won the team title. The U.S. finished third behind West Germany (page 70).

PRO FOOTBALL—Tampa Bay won the third and by far the biggest game of its existence, upsetting Minnesota in Bloomington 16-10. Rookie Quarterback Doug Williams threw a five-yard touchdown pass to Morris Owens in the third quarter, which turned out to be the winning score. The pass came after the Vikings' Kevin Miller allowed a Dave Green punt to glance off him, Billy Cesare of the Buccaneers recovering the ball on the Minnesota five. Undefeated NFC Central leader Chicago scored three times in a four-minute, 19-second span in the third quarter to beat Detroit 19-0. The victory was the Bears' ninth straight in regular-season play, enabling them to match their longest win streak since 1941-42. Green Bay, which had won two straight, hoped to match its best start since 1966 against Oakland, but the Raiders got 151 yards rushing from Mark van Eeghen and two touchdowns from Arthur Whittington to beat the Packers 28-3. Pittsburgh and Cleveland remained unbeaten in the AFC Central. The Steelers defeated win-less Cincinnati 28-3 as Terry Bradshaw completed 14 of 19 passes for 242 yards and directed a Steeler offense that gained 447 yards. Brian Sipe threw two first-half touchdown passes and the Browns survived a second-half Atlanta rally to defeat the Falcons 24-16. Toni Fritsch kicked a 19-yard field goal with 1:14 left to give Houston a 20-19 victory over San Francisco. Washington took over first place in the NFC East. The undefeated Redskins whipped St. Louis 28-10, while Los Angeles, also unbeaten, upset Dallas 27-14. Pat Haden threw a 43-yard touchdown pass to Willie Miller with 7:46 remaining in the fourth quarter to put the Rams in front, then Rod Perry returned a Roger Staubach pass 43 yards for the clinching score with 3:21 left. Tony Dorsett, who had averaged over 100 yards rushing in his first two games, gained just 38 on 19 carries. Kansas City's wing T generated 365 yards against the New York Giants, but Joe Pisarcik's two touchdown passes and Doug Kotar's 79 yards rushing in 10 carries helped the Giants to a 26-10 victory. In New Orleans, Ron Jaworski threw two touchdown passes to 6-8 Harold Carmichael as Philadelphia beat the Saints 24-17 for the Eagles' first victory of the season. David Sims rushed for 121 yards and three touchdowns as Seattle beat the Jets 24-17 in New York (page 67). Miami moved into a first-place tie with the Jets in the AFC East, defeating winless Buffalo 31-24. Gary Davis ran 65 yards for one Dolphin touchdown and Delvin Williams rushed for 125 yards and another score. For Miami, it was the 17th straight victory over the Bills, tying an NFL record. In Denver, Rick Upchurch returned a punt 75 yards for a touchdown with 3:17 remaining, then Lonnie Perrin added insurance with a 21-yard score with 1:33 left as Denver beat San Diego 27-14. On Monday night Minnesota set back the Broncos 12-9 in overtime on a 44-yard field goal by Rick Danmeier.

GOLF—RON STRECK shot an eight-under-par 62 for a 265 total, 15 under par, to win the $200,000 Texas Open at San Antonio by a stroke over Hubert Green and Lon Hinkle.

Donna Caponi Young shot a final-round, two-under-par 71 for a 282 total to win the $100,000 LPGA tournament in Alamo, Calif. by five strokes over Jane Blalock.

HARNESS RACING—FLORIDA PRO ($7.40), driven by George Sholty, won the $113,350 Colonial Trot at Liberty Bell Park in Philadelphia by a length and a half over Doublemint. The 3-year-old was timed in 1:58.1.

HORSE RACING—In the first meeting of Triple Crown winners, SEATTLE SLEW ($6.20), the 1977 champion, Angel Cordero Jr. up, defeated Affirmed, this year's champion, by three lengths to win the $300,000 Marlboro Cup at Belmont. Slew covered the mile and an eighth in 1:45[4/5] (page 22).

MOTOR SPORTS—DANNY ONGAIS, driving an Interscope-Cosworth, averaged 146.246 mph to win the Michigan Grand Prix for Indianapolis-type cars at Brooklyn, Mich. Tom Sneva, in a Penske-Cosworth, finished second, 12 seconds behind.

Bobby Allison, driving a Thunderbird, averaged 119.323 mph on the Dover Downs International Speedway to take a 19.7-second victory in the Delaware 500 over Cale Yarborough, in an Oldsmobile.

TENNIS—The U.S. defeated Chile 3-2 in the American Zone Davis Cup final at Santiago, as Brian Gottfried and John McEnroe won the decisive doubles match over Jaime Fillol and Belus Prajoux 3-6, 6-3, 8-6, 6-3 (page 53).

Virginia Wade defeated Betty Stove 6-4, 7-6 to win the $100,000 Toray Sillook Championship in Tokyo for the second straight year.

WTT—Before the Boston Lobsters and Los Angeles Strings began their best-of-five championship series, it was evident that the Martina Navratilova-Chris Evert match would be the key. But Navratilova reinjured her left shoulder at the U.S. Open and watched from the sidelines as Evert and the Strings won two straight from the Lobsters in Boston and returned to Los Angeles with a chance to sweep. The Strings defeated the Lobsters 24-21 in Match 1 with Evert beating 19-year-old Anne Smith, who was facing Chris for the first time, 6-2, then teaming with Ann Kiyomura to beat Smith and Terry Holladay 6-2. Match 2 illustrated why Navratilova's absence was so critical. With the Lobsters trailing 17-15 entering the fourth set, Evert trounced Smith again 6-0 to assure Los Angeles its second straight road victory.

TRACK & FIELD—STEVE OVETT of Great Britain established a world record of 8:13.5 in the two-mile run at an international meet in London's Crystal Palace. His time was .3 of a second faster than the mark set by Brendan Foster in 1973.

MILEPOSTS—SIGNED: By the Oakland Raiders, former New England Patriot and San Francisco 49er Quarterback JIM PLUNKETT, 30, to three one-year contracts. Plunkett, whom the 49ers placed on waivers before the start of this season, has passed for 13,217 yards and 84 touchdowns in seven years.