Venus Williams watches her Washington Kastles mixed doubles partner Leander Paes dig out a shot in a July 5 match in Washington. The Kastles beat the Philadelphia Freedoms to complete an undefeated World Team Tennis regular season. (Matt McClain/For The Washington Post)

The Washington Kastles wrapped up an unbeaten regular season with a dazzling display of power, shot-making and teamwork Thursday, trouncing the Philadelphia Freedoms, 25-11, before a spirited capacity crowd that braved the sweltering heat.

The Kastles improved to 14-0, becoming only the second squad in the 36-year history of World Team Tennis to compile a perfect mark in regular season play. The other team to do so was the 1994 Newport Beach Breakers (then known as the Dukes).

The Kastles won all five of their sets against the Freedoms, whose roster included Ellicott City’s Beatrice Capra, 19, who reached the third round of the 2010 U.S. Open and will enroll this fall at Duke.

The resounding victory sends the Kastles into this weekend’s playoffs in Charleston, S.C. As the No. 1 overall seed, the Kastles will have home-team advantage, which means Coach Murphy Jensen will decide the order in which the five sets are contested. Washington will play the Boston Lobsters on Friday at 7 p.m.

The Kastles’ strength is their doubles play, anchored by Leander Paes and Rennae Stubbs. Paes was sensational Thursday, making several spectacular shots, including one behind-the-back winner, in his mixed and men’s doubles outings.

The Kastles won the 2009 WTT championship in their second season. Owner Mark Ein kept the nucleus of that squad intact while adding Venus Williams as a second marquee player to complement her younger sister Serena.

With Venus Williams kicking off the 2011 season, the Kastles opened their new home venue this season on the city’s Southwest waterfront, Kastles Stadium on the Wharf, on July 5. Two nights later, with Serena Williams in action, the team drew first lady Michelle Obama and daughters Sasha and Malia to the stands.

Paes credited the team’s perfect record to the inspiration its players get from Ein, Jensen and their vocal fans.

“We are all unique individuals, yet Mark and Murphy have got us all together where we complement each other,” Paes said. “And when you look at playing at home, we have such amazing fan support. I carry that same energy when I go on the road.”