Bermuda are playing the part of laboratory rat in an ambitious experiment by the International Tennis Federation.

As the Davis Cup American Zone Group III and IV championships began yesterday at the Southampton Princess, players suddenly had to learn to play without the let rule.

And while coaches and officials say that losing the let -- a replay of first serves that hit the net -- won't affect play, the move does signal a change in direction for the sport as a whole.

Like other sports, tennis appears to be taking a closer look at its grassroots level, spectators and television ratings.

Thomas Hallberg, the executive director of the ITF's Davis Cup Committee, said yesterday that abolishing the let was part of the game's "modernisation.'' But purists shouldn't be alarmed by this or by calls for a softening of the "power'' game currently in vogue, Hallberg said. "No one wants to change the character of the game,'' he said.

Officials cite several reasons why the let isn't needed, the biggest being that it can add an extra 20 seconds to each point at a time when attention spans are about as long as the next commercial.

Removing the let also allows the ITF to get away with one fewer official, thereby reducing associated costs -- and the physical danger from being hit with balls being served at 125 mph. In that tennis probably has more officials per player than any other sport, this is an important consideration.

On a recreational level, no lets can translate into no arguments among players, officials said.

World Team Tennis in the US did away with the let two years ago -- or about the time the ITF began studying the issue. It will not be universally accepted until it goes before the ITF's annual general meeting in 1998, tournament referee Ken Farrar, a member of the rules committee and the ITF administrator of officiating said yesterday.

This is just the second Davis Cup tournament in which it's been attempted; the first was a Euro-Africa Group III tournament and, Hallberg said, in 240 matches there were a total of about 800 balls that would ordinarily be defined as lets.

Results conformed to the ITF's own studies, which show 75 percent of would-be lets were neutral, meaning they did not work to the advantage of one player.

Fifteen percent were clear aces and the other ten percent resulted in a winning return.

As they will throughout this tournament, chair umpires yesterday kept track of all lets and their result. Ironically, chair umpires had more trouble coping with the rule than the players.

"The first game at centre court, the chair umpire called the first two lets,'' Farrar laughed. "They don't get a chance to practise like the players.'' The adjustment for players appears minimal. There is speculation that particularly skillful servers can use it to their advantage but Farrar is a non-believer. "I don't think they can do it,'' he said. "Players aren't that good.'' Lets or no lets, play got underway yesterday with four Group III ties.

Antigua/Barbuda made the biggest splash on a blustery day, ripping Trinidad and Tobago 3-0 behind singles victories by Fitzroy Anthony and Phillip Williamson.

The other ties were 2-1 affairs but two of them were basically finished after the two singles matches. Wins by Panama's Juan Herrera and Chad Valdez and by Guatemala's Andrea Asturias and Daniel Chavez made doubles losses meaningless against Barbados and Jamaica, respectively.

But a 6-7 (4), 6-2, 6-2 doubles victory by Bolivia's pair Pablo Ugarte and Carlos Navarro clinched a decision over Dominican Republic. Navarro won his singles match over Sixto Camacho while Ugarte lost to Rordo Vallejo.

The round-robin continues today at the Southampton Princess, starting at 10 a.m. Opening ceremonies -- featuring assorted dignitaries -- also take place today after the final matches around 5.30 p.m.

The two lowest-placed teams among the eight Group III nations are demoted to Group IV next year, while two of the three Group IV nations -- who kick off their play tomorrow -- move up.

Hallberg said Group IV -- which is only in its first year -- will expand to seven teams next year. St. Lucia -- currently part of Group IV Organisation of Eastern Caribbean States -- will go it alone, joined by Honduras, Netherlands Antilles and the US Virgin Islands.

Results, schedule, see Scoreboard, Page 14 ONE DOWN -- Davis Cup Group III action got underway here yesterday with Guatemala -- behind Andres Asturias (above) -- defeating Jamaica in one of four ties.