A new custom home in Water Mill South listed for $21.9 million comes with an unusual amenity -- a rooftop tennis court.

The regulation court, the surface of which is the same as the U.S. Open's, comes with 180-degree views of Mecox Bay and the Atlantic Ocean. A mahogany brise-soleil extends from balconies on the second floor, where it acts as a sunscreen to become part of the tennis court's enclosure. Nine-foot-high walls on the other three sides complete the perimeter.

advertisement | advertise on newsday

A staircase and elevator originating in the main hallway of the 13,000-square-foot home lead directly to the tennis court, giving onto a pergola that provides seating.

The seven-bedroom, 8 1/2-bath home comes with an infinity pool and spa, theater, wine room and gym.

Linda Haugevik of Douglas Elliman Real Estate has the listing.