With each team playing its part in a tight battle for second place in the conference, the Fever close their regular-season home schedule against the Sky on Saturday night.
With Washington's win over Connecticut on Friday, the second-place Mystics moved one-half game ahead of Indiana and Chicago, who have identical 15-17 records.
A victory over the Fever would put the Sky in the driver's seat for home-court advantage in the first round with a 3-2 edge in the season series, which is the first tiebreaker. Chicago split four games against Washington but owns the second tiebreaker on the strength of a better conference record.
Things are a lot murkier for Indiana, which also went 2-2 against the Mystics but has just one more victory than them against Eastern opponents.
After Washington closes its regular season at home Saturday against New York it could all come down to Sunday's season finales for Indiana and Chicago. The Fever visit the Liberty, while the Sky host San Antonio.
Delle Donne (Lyme disease) and Fowles (hip surgery) have missed a combined 30 games, the key factor in turning a 5-1 start into a race to finish at .500. With both playing quality minutes of late, Chicago has finally reverted to its early season winning ways.
"It has been interesting in the East and thankfully so," coach Pokey Chatman said. "We've been through a lot, but we're still right there."
Fowles had 21 points and 16 rebounds and Delle Donne scored 18 in a reserve role to lead the Sky to a key 72-69 victory at Washington on Wednesday.
The two combined to shoot 14 of 20, and with the 6-foot-6 Fowles prowling the lane, Chicago owned a 41-29 edge on the glass and outscored the Mystics 42-30 in the paint.
Indiana has won two in a row after a 76-63 home victory over New York on Thursday. Briann January scored 16 points and Tamika Catchings added 15 to help the Fever clinch a 10th straight postseason berth, tying the league record set by Seattle from 2004-13.
"The pieces are starting to click for us," Catchings told the WNBA's official website. "We just have to continue building off what we have."