Guillermo Vilas, Gene Mayer, Jose-Luis Clerc and Ivan Lendl, ranked among the top 10 players in the world by the Association of Tennis Professionals, will be in a field of 64 players for the 13th annual Washington Star International tournament to be played at Rock Creek Tennis Stadium, July 18-27.

The $175,000 tournament, with $28,000 going to the singles winner and $10,500 to the winning doubles team, will display some of the best clay-court talent, said tournament cochairmen Donald Dell and John Harris.

Dell announced that the finals will be held on Monday night instead of Sunday afternoon, as in recent years, to boost attendance and television ratings. The USA cable network will provide television coverage.

Also scheduled to play in the tournament are Eliot Teltscher, defending-champion Brian Gottfried and Yannick Noah. Dell said there is still a possibility that Jimmy Connors will enter, but that Bjorn Borg, the world's top-ranked player, and John McEnroe most likely will not compete.

Qualifying matches are scheduled for July 18-19. A Grand Masters event -- for players 45 or older -- will be held at night on July 18-19, with the final July 20.

Tickets priced from $4 to $12 are available at Arthur Ashe and Friends Tennis Shops, Herman's World of Sporting Goods, Charge-A-Ticket (626-1000), Ticketron and the Washington Star Tournament Office. Students under 18 can buy half-price tickets at the gate July 18-July 23. Senior citizens, military personnel and college students who buy tickets at the gate can get a $1 discount.