Phoenix and Seattle have faced each other in the Western Conference playoffs in each of the past two years.
Neither club has looked much like a postseason contender in 2012.
Meeting for the first time since their highly competitive 2011 semifinal series, the Storm look to bounce back from their latest defeat by trying to hand the visiting Mercury a fourth consecutive loss Sunday night.
Seattle (7-9) has won four straight regular season home games versus Phoenix, but Candice Dupree's putback with 1.9 seconds left gave the Mercury a 77-75 road victory in Game 3 of last season's conference semifinals to eliminate the Storm. That came one year after Seattle swept Phoenix in the conference finals.
Consistent success has eluded both teams this year.
Seattle has won six of eight but is still fourth in the conference and two games below .500. Phoenix (4-12), meanwhile, owns the third-worst record in the WNBA while playing without injured stars Diana Taurasi (hip) and Penny Taylor (knee).
The Mercury pushed Atlanta to double overtime Saturday before falling 100-93, their 10th defeat in 13 games without Taurasi. DeWanna Bonner had 27 points, 15 rebounds and six steals, and rookie guard Samantha Prahalis added 21 points but committed nine turnovers as Phoenix shot 32 percent and blew a 17-point second-half lead.
"We're losing games and I'm not digging it," guard Alexis Hornbuckle told the Mercury's official website after she set season highs of 11 points and 11 rebounds.
Despite the team's overall poor play, Bonner is averaging 26.5 points in her last six contests.
The Mercury did have Dupree back on the floor Saturday for the first time after missing six games with a knee injury. Dupree, who finished with six points in eight minutes, averaged 15.8 points and 5.8 rebounds in nine games before getting hurt.
She totaled 49 points while shooting 22 of 29 in the final two playoff games against the Storm last season.
It's uncertain how many healthy bodies Seattle will have on the floor after losing 83-59 at Los Angeles on Saturday. Already without leading scorer Sue Bird (13.0 points, 5.2 assists per game) and top rebounder Ann Wauters (10.7 ppg, 6.2 rpg), the status of veteran Tina Thompson is uncertain after she injured her leg against the Sparks.
"Like I told the team, 'No one's feeling sorry for us,'" Storm coach Brian Agler said. "Every team has had situations like this before.''
While it's likely Wauters will miss a third consecutive game, Bird hopes to play despite a hip injury.
"If I wake up (Sunday) and feel good, I expect to play,'' said Bird, who averaged 16.6 points in seven regular season and playoff games against the Mercury in 2011.
After playing nine of their last 12 on the road, the Storm return to Seattle, where they have won four in a row since opening the season with a 72-66 loss to the Sparks.
These teams will meet again Friday in Phoenix.