Sloane Stephens made her Kastles debut with a 5-2 women's single win as Washington went on to beat Springfield 23-15.
The Lasers jumped out to an early lead, going up 5-3 in the opening set of men's singles, but Stephens turned things around and gave the Kastles a lead they would hold for the rest of the match with her 5-2 win, putting Washington up 8-7 at the time.
Leander Paes and Bobby Reynolds took men's doubles 5-4, while Martina Hingis and Anastasia Rodionova cruised through women's doubles 5-2.
Paes and Hingis finished things off in mixed doubles 5-2.
The Kastles will finish the regular season in Philadelphia on Wednesday.
Michelle, Malia, and Sasha Obama were amung the 3,200 fans at the sold out Smith Center Tuesday night to see the Kastles pick up home court advantage for their Eastern Conference Championship match on Thursday.
The Kastles picked up their tenth win of the season (10-3) and will play the Philadelphia Freedoms for a chance to advance to the Mylan WTT Finals on Sunday.