Anne Worcester, the longtime director of the Pilot Pen tournament, is delighted.

"It was a major investment," Worcester said. "But it makes tennis more fan-friendly, more exciting and we're 100 percent sure we wanted to be a part of it."

The first round gets under way Sunday and ends with title matches Aug. 26 in the coed field, the final tuneup before the US Open. The event features defending champions Lindsay Davenport and James Blake.

The Pilot Pen is part of the US Open Series that links 10 ATP and WTA Tour tournaments to the US Open, offering bonus money to those who finish atop the series rankings.

Earlier this season, both tours instituted instant replays for various tournaments, including the Pilot Pen. This year's US Open will be the first Grand Slam event to review disputed line calls electronically. Worcester called it the biggest innovation in the sport since the tiebreaker.

The fans and players seem to like it, but it comes with a price -- nearly 100,000 dollars. Worcester said tournaments need 40,000 dollars for the technology and about 50,000 dollars for a big-screen Jumbotron, but do get financial help from the US Tennis Association and both tours.

"Electronic line calling trialed in Miami and was found to be very entertaining for the fans," Worcester said. "As soon as the players call a challenge, all eyes go to the Jumbotron."

The Pilot Pen also is one of only two venues this season that the WTA has chosen to test on-court coaching. Players may request their coach on court once per set and during set breaks. During their on-court conference, they'll be wired for sound for the benefit of the television audience, Worcester said.

There are some logistics that have to be worked out.

"Where do the coaches sit? How do we get the mike to the player? What if there's a foreign language? There's a thousand issues," Worcester said. "It's just very much in its infancy. The jury is still out on whether it will be formally adopted."

The women's field features the world's No. 1 player in Amelie Mauresmo, winner of two Grand Slam events this year, and the 2005 Pilot Pen runner-up, Justine Henin-Hardenne. She is coming off a knee injury and playing her first tennis since losing to Mauresmo in the Wimbledon final.

The men's side includes Nikolay Davydenko, Marcos Baghdatis, Jarkko Nieminen and David Ferrer.

The 1.25 million dollar purse offers 600,000 dollars in prize money for the women's field and 650,000 for the men.