Undated (AP) _ FUJISAWA, Japan (AP) -Top-seeded Felix Barrientos of the Philippines beat Japan's Shigefusa Kanroji 6-4, 6-4 Wednesday in the second round of boys' singles in the JAL Cup international junior tennis tournament.

In girls' singles, top-seeded Mitsuko Yokota of Japan defeated compatriot Yasuko Nozaki 6-2, 6-2 at Shonan Sports Center.

This is the last leg of a nine-round Asian junior tennis circuit, on which Barrientos already has won twice, including last week's tournament in Taipei, Taiwan.

Playing in the six-day competition are 96 boys and girls under 18 years of age from 16 countries - the Philippines, Indonesia, Mexico, Australia, China, Taiwan, India, the United States, Sri Lanka, Hong Kong, Brazil, South Korea, Thailand, West Germany, Britain and Japan. ---

TOKYO (AP) - Fomer major leaguer Bombo Rivera had a solo home run as the the Kintetsu Buffaloes rapped out 17 hits and beat the Nankai Hawks 11-4 Wednesday in a Japanese League baseball game. ---

MONZA, Italy (AP) - Several Formula One drivers will compete in Sunday's 1,000-kilometer of Monza auto race, which counts toward the 1985 World Endurance Championship, organizers announced Wednesday.

The Belgian-German team of Jacky Ickx and Jochen Mass, winners of the 1,000-kilometer of Mugello earlier this month, will lead a powerful lineup of German Porsche cars, which are the heavy favorites in the event.

Other Porsche drivers included Thierry Boutsen of Belgium, Stefan Bellof and Manfred Winkelhock of West Germany and Jonathan Palmer of Britain.

Italian ace Riccardo Patrese will drive a Lancia-Martini in the race, held on the same track which will host the Grand Prix of Italy's Formula One race in September. ---

OMAEZAKI, Japan (AP) - America's top wind surfer Robby Naish won the men's slalom while France's Nathalie le Lievre captured the women's event Wednesday in the wind surfing World Cup series.

Naish received 16 points from six judges at the meet at Omaezaki, 112 miles southwest of Tokyo, in winds of 33 miles an hour under clear skies.

The Omaezaki meet, officially called ''Sometime World Cup '85,'' is the first of a series of five. The second is to be held in San Francisco, California, June 21-30, the third in Sylt, West Germany, Sept. 20-29, the fourth in Scheveningen, the Netherlands, Oct. 4-13 and the fifth in La Torche, France, Oct. 18-27. ---

HAMILTON, Ontario (AP) - The Hamilton Tiger-Cats have signed slotback Steve Jackson and import running back Elmer James, the Canadian Football League club announced Wednesday.

Jackson rejoins the Ticats after being on their active roster in 1984.

The 24-year-old was a two-year all-star with Guelph Gryphons of the Ontario Universities Athletic Association, prior to his signing with Hamilton.

James played with the Los Angeles Raiders of the National Football League in 1984. Prior to that, he was with Oakland Invaders of the United States Football League for the 1983 season.

The 24-year-old resident of Carson, Calif., played his last collegiate year in 1982 with San Francisco State.