World Chess Champion tigran Petrosian of the Soviet Union has suffered his first defeat since he won the international title a month ago.

Petrosian lost to Svetozar Gligoric of Yugoslavia in the second round of the first Piatigorsky Cup Tournament at Los Angles California (American West Coast), on 3 July 1963.

Three hundred fans viewed the match, which ended with 12 moves made in the last five minutes.Gligoric scored a full point with the victory.He now is tied for the lead in the chess tourney with Miguel Najdorf of Argentina.

In other matches, Pal Benko of the United States and Paul Keres of the Soviet Union adjourned after 40 moves.Oscar R.Panno of Argentina and Samuel Reshevsky of the United States also adjourned.

Playoffs in both matches will be held on Friday (5 July).

Fredrik Olafsson of Iceland and Jandorf ended in a draw after 16 moves, giving each a half point.

The third round in the month-long tournament will be held on 7 July.