ATLANTA — Alex Bentley came off the bench to score 21 points and the Atlanta Dream evened their WNBA semifinal playoff series against Washington with a 78-75 victory Tuesday night, but the game was marred in the closing minutes when Mystics star Elena Delle Donne went down with what looked to be a serious knee injury.

Delle Donne had another huge game with 27 points, 14 rebounds, six assists, two blocks and a steal, giving the Mystics a chance to take control of the best-of-five series with a second straight road win.

Then, with just over 3 minutes remaining and Washington clinging to a 70-68 lead, Delle Donne stumbled on a drive to the basket and collapsed to the court, clutching her left knee.

The entire Mystics team raced to her side at the opposite end of the court, some turning away in dismay when they saw Delle Donne writing on the court in pain.

The injury may deprive the series of two of its biggest stars. The Dream already was missing its longtime leader, Angel McCoughtry, who went down late in the season with a knee injury and cheered on her teammates from the bench.

STORM 91, MERCURY 87, OT

SEATTLE (AP) — Sue Bird scored 19 points, including the go-ahead basket with 1:03 left in overtime and two clinching free throws with 2.1 seconds left, to help the Seattle Storm recover from blowing a 17-point fourth quarter lead and beat the Phoenix Mercury 91-87 in the second game of the WNBA semifinals Tuesday night.

Seattle now has a 2-0 lead in the best-of-5 series, having won Sunday's first game by an identical score.

Breanna Stewart led Seattle with 27 points, getting 14 of those in the third quarter to help the Storm build a 19-point advantage.

But Phoenix, which was still down by 17 at 73-56 with six minutes left, went on a 23-6 run to end regulation, tying it on an incredible 3-pointer from the left corner by Diana Taurasi with 3.7 seconds left. It was her third trey in the final 1:36 of the fourth quarter. Taurasi finished with 28 points.

Stewart had a chance at the game-winner for Seattle in regulation, but her turnaround shot from the right of the hoop bounced off the rim.