WASHINGTON -- Elena Delle Donne scored 24 points and Sylvia Fowles added 16 points and 15 rebounds as the Chicago Sky moved closer to their first playoff berth with a 79-73 win over the Washington Mystics on Tuesday night.
Courtney Vandersloot had a season-high 19 points and seven assists for the Sky (18-8), who rallied back from a double-digit deficit for the second straight game.
The Eastern Conferences leaders reduced their magic number for clinching a playoff spot to one and can secure it with a win against New York on Friday.
Kia Vaughn scored a season-high 21 points for the Mystics (12-15), losers of two straight. Washington led by 11 points after one quarter, but fell behind after going nearly 11 minutes without a field goal in the second half.
Delle Donne made three 3-pointers in her return from a two-game absence after spraining her left foot against Los Angeles on Aug. 13. The starry rookie previously missed two games earlier in the month and the WNBA All-Star game following a concussion here on July 24.
Without Delle Donne, the Sky stormed back from a 25-point deficit for an 89-78 home win over Connecticut on Sunday.
Ivory Latta had 12 points for the Mystics, winners of a combined 11 games the previous two seasons. The loss dropped Washington into a statistical tie with idle Indiana for third place in the Eastern Conference.
The Mystics led 41-37 at halftime, but shot 1 for 16 from the field in the third quarter. After Tierra Ruffin-Pratt's layup with 7:22 left in the third, they missed 15 straight attempts until Vaughn's jumper with 6:28 remaining in the game.
Despite Washington's shooting struggles, Chicago could not pull away due to its own inaccurate ways, but never relinquished the lead in the tense final minutes.
Vandersloot's 3 from the right wing with 1:14 remaining made it 73-68 and the point guard drew a charge from Monique Currie on Washington's next possession. Chicago made 4 of 6 free throws over the final 32 seconds.
Vaughn entered averaging 5.5 points in 26 games this season, having gone 10 straight games without a double-digit performance. She smashed her previous season-high of 10 points in the first quarter and had 17 by halftime.
In the third quarter, Vaughn briefly left the game after taking an inadvertent blow to the head and scored only four points in the second half.
After missing six of their opening seven field-goal attempts, the Mystics went on a 12-0 run and led 28-17 after the first quarter. Vaughn scored 13 points in the first including a stretch five straight Washington baskets.