A roundup of the week Oct. 15-21

BOXING—MARVELOUS MARVIN HAGLER retained his WBA middleweight title with a third-round TKO of Mustafa Hamsho in New York (page 30). On the same card, MIKE McCALLUM scored a unanimous 15-round decision over Sean Mannion to win the vacant WBA junior middleweight crown.

PRO FOOTBALL—NFL: As the season reached the halfway point, the wide range between excellent teams and execrable ones became more boldly etched. Miami, 8-0 and leading the AFC East, solidified its front-running position as Dan Marino riddled New England (5-3) for 316 yards and four touchdowns in a 44-24 victory (page 24). The most surprising upper-echelon team is Denver (7-1), which maintained its first-place tie in the AFC West with an opportunistic defense. On Monday the Broncos scored after fumble recoveries on the first two plays from scrimmage and held off Green Bay 17-14. Then, on Sunday, Denver crushed Buffalo 37-7 with the aid of five more turnovers. The Raiders kept pace with the Broncos by beating San Diego 44-37 as Marc Wilson threw five TD passes. In the NFC West, first-place San Francisco (7-1) continued to roll with a 34-21 victory over hapless—and winless—Houston. The NFC East has yet to produce a dominant team, but St. Louis made its bid with a 26-24 defeat of Washington as the Cardinals' heart-stopping kicker, Neil O'Donoghue, booted the 21-yard winner with :03 left. That triumph, coupled with Dallas's 30-27 OT defeat of New Orleans, left the Cards, Skins and Cowboys tied at 5-3, with Philly and New York only a game back after the Eagles beat the Giants 24-10. The Chicago Bears won their showdown with Tampa Bay by blowing out the Bucs 44-9 and opened up a two-game lead in the NFC Central. In the most dreadful of divisions, the AFC Central, Pittsburgh (4-4) still leads by two games despite having lost to the Colts 17-16 on Ray Butler's 54-yard TD reception of a deflected pass with :34 remaining. The Jets (6-2) maintained their upper-middle-class status with a 28-7 win over Kansas City, and Detroit (3-5) struggled back toward respectability by beating Minnesota 16-14. Among the untouchables, Green Bay (1-7) dropped another one, 30-24 to Seattle, and the Battle of Ohio turned into a war of attrition as Cincinnati (2-6) beat Cleveland (1-7), four field goals to three.

GOLF—LARRY NELSON shot a 22-under-par 266 to win a $400,000 PGA event in Lake Buena Vista, Fla. by one stroke over Hubert Green.

HOCKEY—After somewhat sluggish starts, Edmonton's Wayne Gretzky and the Islanders' Mike Bossy picked up where they left off a year ago—and gave their teams pick-me-ups in the process. Gretzky, who scored only one goal in the Oilers' first three games, exploded for a hat trick in Edmonton's 7-5 win in Minnesota, and then added two more goals in a 7-4 defeat of Winnipeg and another two in a 6-4 win over Calgary as the 6-0-1 Oilers, who pace the Smythe Division, remained the only unbeaten team in the NHL. Bossy, who had one score in each of the Islanders' first two games, picked up the pace last week with two goals in a 6-4 win over New Jersey and four more in an 8-3 beating of Los Angeles. That gave the Isles four straight wins before they dropped a 6-5 decision to the Rangers. Bossy now has 30 NHL hat tricks, only two behind career leader Phil Esposito. A player who used to be among the league's elite, Guy Lafleur of Montreal, broke a personal streak of 30 scoreless games as the Canadiens beat the Flyers 5-2. But the real surprise in the Adams Division is Hartford. The Whalers won three times, 5-3 in Toronto, 7-3 over Detroit and 3-2 over Vancouver, to go three games over .500 for the first time since they joined the NHL in 1979. In the Norris Division, St. Louis moved to the top with an 8-3 thrashing of the Devils that featured three goals and two assists from Kevin LaVallee.

HORSE RACING—SLEW o' GOLD ($2.20), with Angel Cordero Jr. up, romped to a 9¾-length victory over Hail Bold King in the $584,000 Jockey Club Gold Cup at Belmont. The 4-year-old colt ran the 1½ miles in 2:28[4/5] and, as a result of sweeping the three-race fall championship series at Belmont, earned a $1 million bonus (page 22).

Script Ohio ($76), with Eddie Maple in the irons, won the $500,000 Young America Stakes at the Meadowlands by three-quarters of a length over Spend a Buck. The 2-year-old colt covered the 1[1/16] miles in 1:45.

MOTOR SPORTS—ALAIN PROST, in a McLaren TAG-Porsche, finished 13.425 seconds ahead of teammate Niki Lauda to win the Portuguese Grand Prix in Estoril, but Lauda's second-place finish allowed him to win the 1984 World Grand Prix driving championship by half a point over Prost. Prost averaged 112.185 mph for the 71 laps on the 2.647-mile road circuit.

Bobby Rahal, in a March 84C, finished 13.17 seconds ahead of Mario Andretti, in a Lola T-800, to win a $360,000 CART event in Monterey, Calif. Rahal averaged 116.619 mph for the 98 laps on the 1.9-mile road course at Laguna Seca Raceway.

Bill Elliott, in a Ford, won a $283,415 NASCAR Grand National race in Rockingham, N.C. by two feet over Harry Gant, in a Chevy. Elliott averaged 112.617 mph for the 492 laps on the 1.017-mile D-shaped oval at the North Carolina Motor Speedway.

TENNIS—JIMMY CONNORS defeated Ivan Lendl 6-4, 3-6, 6-0 to win a $300,000 Grand Prix tournament in Tokyo.

Matt Mitchell upset Pat Cash 6-4, 3-6, 6-2 to win a $150,000 Grand Prix tournament in Melbourne, Australia.

TRACK & FIELD—STEVE JONES of Wales won the America's Marathon in Chicago over an especially flat course in a world-best time of 2:08:05, trimming eight seconds off the mark set by Alberto Salazar in New York City in 1981.

WEIGHTLIFTING—NAIM SULEIMANOV of Bulgaria surpassed by one pound the 123-pound-class world record set by the U.S.S.R.'s Osken Mirzoyan with a snatch of 295 and ran his own world records in the clean and jerk to 380 and the Olympic combination to 672, in Belgrade, Yugoslavia.

MILEPOSTS—FILED: By the USFL, a lawsuit against the NFL alleging antitrust violations and seeking treble damages of $1.3 billion.

NAMED: As manager of the Boston Red Sox, JOHN McNAMARA, 52, replacing Ralph Houk, who retired at season's end after four years with the Sox and a record of 312-282. McNamara, who resigned as the California Angels' skipper Oct. 9 with a 151-173 mark, was replaced on the Angels by GENE MAUCH, 58, who returns to the job he left in favor of McNamara in 1982.

PENALIZED: By the USFL, with a fine of $50,000 and the loss of its 1985 No. 1 draft pick, the DENVER GOLD, for tampering in the signing of coach Darrel (Mouse) Davis. The league ruled that the Gold hadn't sought the permission of the Houston Gamblers, for whom Davis was an assistant.

TRADED: By the Boston Celtics, guard GERALD HENDERSON, 28, to the Seattle SuperSonics for a first-round draft choice in 1986; and by the Indiana Pacers, guard BUTCH CARTER, 26, to the New York Knicks for a No. 2 pick in 1985.