BOXING—ESTEBAN DeJESUS of Carolina, Puerto Rico retained his WBC lightweight title in San Juan with a seventh-round knockout of Hector Julio Medina of the Dominican Republic.

PRO FOOTBALL—The Super Bowl Champion Pittsburgh Steelers stumbled in their opener, losing to Oakland 31-28 on rookie Fred Steinfort's 21-yard field goal with 18 seconds remaining. The Steelers led 28-14 with only three minutes to play, but the Raiders tied the score on Ken Stabler's touchdown rollout and went on to win after Willie Hall intercepted Terry Bradshaw's pass at the Steelers' 17-yard line. Cincinnati's Ken Anderson threw two touchdown passes in the last 10 minutes as the Bengals beat Denver 17-7, and Roger Staubach threw for 242 yards and two touchdowns as Dallas defeated Philadelphia 27-7. Chicago rallied for a 10-3 win over Detroit. Houston rolled up 190 yards on the ground to beat Tampa Bay 20-0; Minnesota clobbered New Orleans 40-9; and Los Angeles defeated Atlanta 30-14 as Ron Jaworski and Pat Haden threw for touchdowns. Washington's Billy Kilmer hit Mike Thomas with a five-yard touchdown pass with 45 seconds to play to enable Washington to beat the New York Giants 19-17. Mike Phipps and Brian Sipe combined for five touchdown passes in Cleveland's 38-17 rout of the New York Jets. Phipps threw three scoring passes before leaving in the third quarter with a separated shoulder. San Diego surprised Kansas City 30-16, and Delvin Williams ran 59 yards for the go-ahead touchdown in San Francisco's 26-14 defeat of Green Bay. Jim Otis and Terry Metcalf both ran for more than 100 yards and Jim Hart passed for two touchdowns as St. Louis spoiled Seattle's NFL debut 30-24. Baltimore defeated New England 27-13 (page 49).

GOLF—RAY FLOYD birdied the first hole of a playoff against Jerry McGee to win $40,000 top money in the World Open at Pinehurst, N.C. Floyd had also birdied the 72nd hole to tie McGee at 10-under-par 274.

Jane Blalock of Portsmouth, N.H. shot an 11-under-par 205 to win the $50,000 Dallas Civitan Open by nine strokes over Kathy Whitworth.

HARNESS RACING—OIL BURNER ($3.40), driven by Ben Webster, won the $101,000 Holmes Pace at The Meadowlands in East Rutherford, N.J. Armbro Ranger won the first heat in 1:56⅘ and Oil Burner the second in 1:56 3/5. Those heats were worth $30,300 apiece; the finale, won by Oil Burner in 1:55 1/5, offered a $40,400 prize.

HORSE RACING—REAL WIND ($5), Gary Sumpter aboard, finished 1¼ lengths ahead of Lord Winsalot to take the $330,000 winner's share in the $1-million All American Futurity—the richest horse race in the world—at Ruidoso Downs, N. Mex. The undefeated 2-year-old filly, who went into the lead midway through the 440-yard race, was timed in 21.7 seconds.

Riot In Paris ($6.60), ridden by Bill Shoemaker, won the $100,000 Del Mar Handicap by three-quarters of a length over favored Avatar. It was Shoemaker's 114th victory in races worth $100,000 or more. Riot In Paris was clocked in 1:57[2/5] over a course that measured 120 feet less than 1¼ miles.

Making his first start on turf, JOACHIM ($22), ridden by Sam Maple, won the $128,400 Secretariat Stakes at Arlington Park. Carrying top weight of 123 pounds, Joachim covered the mile and an eighth in 1:50[4/5].

Dance Spell ($17.60), ridden by Ruben Hernandez, won the $111,000 Jerome Handicap at Belmont Park, scoring a 3¾-length victory over Soy Numero Uno. Dance Spell covered the mile in 1:35.

MOTOR SPORTS—RICHARD THARP of Houma, La. won the top fuel class at the National Hot Rod Association Championships at Indianapolis, covering the quarter mile in 6.114 seconds. In Funny Car competition, GARY BURGIN of Stanton, Calif., driving a '76 Mustang II, upset Don Prudhomme of Granada Hills. Calif.; Burgin's time was 6.258. Prudhomme, who had won seven straight NHRA titles this year, set a national record of 5.97 in a qualifying heat. In pro stock competition, WALLY BOOTH of Berkley, Mich., driving a '75 Hornet, was timed in 8.692, defeating Larry Lombardo of Malvern, Pa., who drove a '76 Monza.

David Pearson, averaging 120.534 mph, won the Southern 500 stock-car race at Darlington, S.C. in his Mercury. Pearson, who had won the Daytona 500 and World 600, took the lead with 56 miles to go and held off runner-up Richard Petty. Pearson collected $16,155.

Cale Yarborough resisted a late challenge by Bobby Allison to win a car-length victory in the Capital City 400 Grand National stock-car race at Richmond. Driving a Chevrolet, Yarborough averaged 77.993 mph on the half-mile track and won $9,250.

Ronnie Peterson of Sweden, driving a March Ford, won the Italian Grand Prix on the 3.7-mile Monza course before a crowd of 140,000. Peterson covered the 187 miles in 1:30:35.6 (an average speed of 124 mph) to defeat Switzerland's Clay Regazzoni, who was driving a Ferrari. In his first race since he was seriously injured in a crack-up in West Germany, Niki Lauda finished fourth.

TENNIS—JIMMY CONNORS defeated Bjorn Borg in the men's singles final of the U.S. Open at Forest Hills (page 10). Connors fought off four set points in a third-set tie breaker as he won the $30,000 top money 6-4, 3-6, 7-6, 6-4. CHRIS EVERT took the women's title, beating Evonne Goolagong 6-3, 6-0 for $30,000. MARTY RIESSEN and TOM OKKER won the men's doubles title, defeating Paul Kronk and Cliff Letcher 6-4, 6-4. BILLIE JEAN KING and PHIL DENT beat Betty Stove and Frew McMillan 3-6, 6-2, 7-5 in mixed doubles.

VOLLEYBALL—The SAN DIEGO BREAKERS, led by league MVP Dodge Parker, defeated defending champion Los Angeles 2-12, 12-3, 12-9, 12-6 to win the IVA title at the San Diego Sports Arena.

MILEPOSTS—ACQUIRED: By the New York Nets, Guard NATE (Tiny) ARCHIBALD from Kansas City in exchange for Guard BRIAN TAYLOR, Center JIM EAKINS and the Nets' first-round draft choices in 1977 and 1978. The 6'1" Archibald has averaged 25.2 points and 8.1 assists in his six NBA seasons.

PURCHASED: By the New York Knicks, Forward JIM McMILLIAN from Buffalo for a reported $200,000. The 6'5" McMillian has a 15.9 points-per-game average for his six NBA seasons. At the same time Knick Forward BILL BRADLEY confirmed reports that he would retire at the end of the 1976-77 season.

SIGNED: By the Buffalo Bills, O.J. SIMPSON, to three one-year contracts at a reported salary of $2.5 million plus substantial fringe benefits. Simpson, 29, had requested to be traded to a West Coast team in order to be closer to his family, but the Bills were unable to come to terms with either the Los Angeles Rams or the Oakland Raiders. The new contract makes Simpson the highest-paid player in NFL history.

RULED: By U.S. District Court Judge WILLIAM B. BRYANT, that the National Football League's annual college draft violates federal antitrust laws.