Instant Replay set to consign line disputes into history

LONDON, Aug 21 (Reuters) Twenty-five years after John McEnroe yelled at an umpire 'You cannot be serious, that ball was on the line... chalk flew up!', such tirades could become a thing of the past when Instant Replay makes it grand slam debut at the U.S. Open next week.

McEnroe's frequent outbursts may have made a case for introducing the technology decades ago.

But it was a controversial call during the 2004 U.S. Open quarter-final between Serena Williams and Jennifer Capriati which propelled the United States Tennis Association (USTA) to try an eliminate human error from officiating.

The system uses Hawkeye technology -- available to television viewers for several years -- as an on-court officiating tool.

Electronic line-calling can measure ball position to within three millimetres using eight court cameras. Players have up to three challenges per set but lose a challenge if they incorrectly question a call.

With the replay flashed simultaneously to the umpire and on the giant scoreboards, courtside fans can follow the drama as it unfolds.

Launched on the regular tour in March at the Nasdaq-100 Open in Miami, many believe Instant Replay is the greatest innovation introduced to the sport since tiebreaks were implemented in the early 1970s.

On its debut outing, a total of 161 calls were challenged during the men's and women's combined event. With 53 calls overturned, it highlighted the rate of human error that usually takes place during the course of a tournament.

''With the speed and power of today's game, the time has come for tennis to benefit from new technology, while adding to the fan experience,'' Arlen Kantarian, chief executive for professional tennis at the USTA, said in March.

''This new breakthrough will improve line calls for players, while adding excitement and intrigue for fans and TV viewers.'' MORE REUTERS PDS VP0905