Sloane Stephens, left, talks with Coach Murphy Jensen while playing in her singles match at Smith Center. (Toni L. Sandys/The Washington Post)

Sloane Stephens was growing impatient, so she finally gave Washington Kastles owner Mark Ein an ultimatum: Draft me to your team or you’re excommunicated. It worked out for both, as Stephens led the Kastles to a 23-15 win over the Springfield (Mo.) Lasers on Tuesday night at Smith Center.

“I’ve always wanted to play on this team,” Stephens said before the match. “Every time I saw Mark, I’m like, ‘Why haven’t you drafted me? How come you haven’t picked me? What’s the hold-up? What’s the problem?’ So, finally, at Indian Wells, I got him this year and was like, ‘If you don’t draft me, I’m never speaking to you again.’ And I’m here.”

With first lady Michelle Obama watching in the stands, the Kastles (10-3) clinched home court for World Team Tennis’s Eastern Conference championship between Washington and the Philadelphia Freedoms on Thursday. Stephens, the No. 22 player on the WTA Tour, helped the Kastles win both sets she played in — women’s singles and doubles.

“I was just happy I got the opportunity to play, and I had so much fun,” Stephens said. “It helped that I played well.”

With her women’s singles set against Olga Govortsova tied at one game apiece, Stephens lost the third game, her expression stoic. She then won the fourth game, 4-1. After two consecutive points in the fifth game, she fist-pumped, mouthing, “yes” to herself. After she hit one into the net later in the set, Stephens covered her mouth in shock.

The result was ultimately what she and the Kastles wanted, a 5-2 win that gave the Kastles a one-game lead in the match. Stephens played against the Kastles twice in 2009 when she was with the New York Buzz.

“You get to just have a lot of fun and enjoy yourself,” Stephens said. “You’re playing against people you play against all of the time, just in a different format. Obviously, it’s very competitive. I love to compete and I want to win all of the time, so I think it’s very good for me to be on this team.”

The match didn’t start well for the Kastles. Bobby Reynolds lost the first set to Springfield’s Michael Russell, 5-3, in men’s singles. But Washington rebounded, winning the tiebreaker in the men’s doubles set, 5-4, and then winning women’s doubles, 5-2. The Kastles had an 18-13 lead going into the mixed doubles set, which they won, 5-2, to take the match.

“We’ll get home-court advantage,” Washington’s Martina Hingis said. “The atmosphere tonight was amazing, so I’m looking forward to it.”