THE SIDELINES : Injured McEnroe Out of Tourney

John McEnroe has withdrawn from next week’s New South Wales Open with a back injury, a tournament spokesman said today.

McEnroe hurt his left shoulder during practice near his Los Angeles home, his agent said late Thursday.

The 31-year-old left-hander was planning to use the New South Wales Open at Sydney’s White City courts as a tuneup for the Australian Open beginning Jan. 14 in Melbourne.

Meanwhile, at Brisbane, two-time champion Helena Sukova defeated Argentine teen-ager Cristina Tessi today to advance to the semifinals of the Danone Open tennis championship. Sukova, the tournament champion in 1984 and 1989, won her third straight match without dropping a set, downing Tessi 6-2, 6-1.

And at Adelaide, Swedish teen-ager Niclas Kulti overpowered Frenchman Fabrice Santoro in straight sets to advance to the semifinals of the Australian Hardcourt tennis championships. Kulti, 19, who is ranked 51st in the world, defeated Santoro 6-3, 6-0. It was the only quarterfinal played before heavy rain swept onto the open-air Memorial Drive Stadium courts.