Tennis: Bodyguards keep eye out for trouble: Courier chases Parisian idyll: John Roberts in Paris reports on the leading prospects for the French Open which starts today amid increased security

THE Centre Court stands at Roland Garros were crowded here yesterday on the eve of the French Open. Charitable spectators saw Jim Courier defeated by Carlos Costa, of Spain, 9-4, for the benefit of the Arthur Ashe Foundation.

Courier used the occasion to practise. So, too, did a pair of bodyguards seated immediately behind the umpire's chair. Wearing trademark sunglasses and navy blazers with beige slacks, they rose and scrutinised the spectators at the changeovers. At the end of the match one of them escorted the players off the court.

If a reminder was needed that this is the first Grand Slam tournament since the knife attack on Monica Seles in Hamburg less than a month ago, the minders served the purpose well.

Seles, the world No 1, is unable to defend her title here and has also ruled herself out of Wimbledon a month from today. If it is any consolation to the dark lady of the punnets, she will be missed.

Andre Agassi has been here, but only to talk. The Wimbledon champion cannot play because of tendinitis in his right wrist, but at a press conference organised by Nike, whose clothes he wears, the Las Vegan vowed to defend his title at the All England Club, fit or otherwise. He said he intends to rest for a further two weeks and then plans to participate in the German grass-court event in Halle as preparation for Wimbledon.

Courier may miss Agassi here more than most. His fellow Nike client has become something of a talisman en route to winning the title for the past two years. Courier required five sets to defeat Agassi in the 1991 final, but overwhelmed him in straight sets in the semi-finals a year ago.

Though supplanted by Pete Sampras as the world No 1, Courier's impressive groundstrokes are tailored for the red clay courts. A creature of habit, if his triumphal dives into Melbourne's Yarra River are a guide, he comes into the tournament, as last year, on the crest of victory in the Italian Open.

Those who watched Costa's shots pass Courier in yesterday's exhibition set may have wondered how many challengers would have similar success when the serious business starts. Roberto Azar, ranked No 93, has first crack at the champion today, though the only possible advantage the Argentinian has over Courier is that he speaks fluent French.

If we are to see a new champion it would benefit the sport if the unusual happened and a predominantly attacking player won on the slower surface, a feat on a par with how Agassi confounded Wimbledon from the baseline.

Stefan Edberg and the coachless Boris Becker usually come here more in hope than expectation, but Michael Stich, another former Wimbledon champion, can adapt his style if his patience holds. Ditto Goran Ivanisevic. Marc Gollner, a German newcomer, has a powerful all-court game but lacks experience.

Even though the Centre Court appears to play faster year by year, the event still favours the baseliner, and the draw features some promising young contenders. Among these are Sergi Bruguera, of Spain, twice a winner of the Monte Carlo, and the Ukrainian Andrei Medvedev.

Medvedev, 18, is particularly interesting. Viewed as the outstanding prospect in the men's game, he recently had cause to drop his customary humour in the interview room when defeated by Guillermo Perez- Roldan in Rome.

He meets the Argentinian again in the opening round here, and if Medvedev advances to the quarter- finals he could face last year's runner- up, Petr Korda, who outsmarted him in the Australian Open. The young man ought not to be short of motivation.

The absence of Seles would make Steffi Graf a clear favourite to add to her successes here in 1987 and 1988 but for lingering doubts about the Wimbledon champion's confidence.

Graf, who opens the tournament against Cecilia Dahlman, of Sweden, may be in a better frame of mind before she is tested by one or other of her chief rivals, Gabriela Sabatini or Arantxa Sanchez Vicario.