San Antonio (13-17) has dropped a season high-tying three in a row and eight of 10, but is two games ahead of Tulsa and 2 1/2 in front of Seattle in the race for the Western Conference's final postseason spot with four to play. The Stars took league-leading Phoenix into overtime Thursday, but the Mercury held them to five points in the final 3:55 in a 78-73 loss.
With a season-high 24 points, Jia Perkins was the only Stars player with more than 10. Hammon was held scoreless, missing three shots from 3-point range, and had one assist in her first game after being hired as the NBA's first full-time female assistant by the San Antonio Spurs on Tuesday.
"It's a tough loss," Perkins said. "We really needed that game. We hung in there, we fought, but we just came up short."
Having won three of four over Tulsa (11-19), San Antonio has already clinched the head-to-head tiebreaker. The Stars, though, went 1-3 versus Seattle, and their magic number is two versus the Storm, who host Tulsa on Sunday night.
The Stars will try to cut that down to one with another win against the Shock. San Antonio posted all three of its previous wins in the series at home and lost 95-90 in its only visit to Tulsa on July 17.
Sims had 15 points in that victory before starting her hot stretch by scoring a career-high 39 in the finale of the home-and-home set, a 95-93 loss July 22. She scored 30 points in a 96-90 win in Los Angeles on Tuesday and is averaging 25.0 points while shooting 52.0 percent in the last seven games.
Skylar Diggins had a career-best 34 in the most recent game against San Antonio. Kayla McBride, taken No. 3 overall in this year's draft and one spot behind Sims, had a team-best 26 points for the Stars.
McBride scored a season-high 30 in an 82-79 win over Tulsa on May 28. She averaged 20.0 points and shot 54.5 percent in a three-game stretch before being limited to eight on 3-of-14 shooting Thursday.