Sue Bird’s retirement tour is extended for at least one more postseason series.

The No. 4-seeded Seattle Storm held off the No. 5 Washington Mystics for a 97-84 win Sunday at Climate Pledge Arena in Seattle to sweep the best-of-three first-round series.

Bird had 18 points and 10 assists for the Storm, her third postseason game with 15-plus points and 10-plus assists. Briann January also is retiring at the end of the season.

The Storm will face the top-seeded Las Vegas Aces in the semifinals, beginning next Sunday in Las Vegas.

Breanna Stewart didn’t hit a field goal in the first half, but dished out six assists. In the second half, she found her rhythm and nearly notched a postseason triple-double with 21 points, 10 rebounds and eight assists to lead the Storm.

Jewell Loyd, who did not have a field goal until the fourth quarter in Game 1, came out firing early in Game 2. She finished with 19 points, including five 3-pointers.

The Storm stretched their lead early in the fourth quarter and shot 55.6% from the field and 52.2% from 3-point range for the game.

Gabby Williams left the game in the third quarter with a concussion and did not return. She had 14 points before the injury, providing an offensive spark for Seattle.

The Mystics trailed by 10 points after the first quarter, then fought back to within two points at halftime. Another back-and-forth game saw 10 lead changes.

Natasha Cloud led Washington with 21 points, six rebounds and five assists. Ariel Atkins added 15 points, and Elena Delle Donne and Shatori Walker-Kimbrough each had 12.

How the Storm won Game 2

Seattle moved the ball well without turning it over, notching 26 assists to eight turnovers. Bird was especially efficient with 10 assists against one turnover.

The ball movement got each Seattle starter into double-digit scoring. The Storm will need this type of unselfish play as the lower seed against the Aces in the next round.

What to watch in the semifinals

The MVP race between Stewart and the Aces' A'ja Wilson is bound to produce some on-court fire. Stewart averaged 21.4 points, 7.4 rebounds and 2.9 assists in the regular season, while Wilson had 19.5, 9.4 and 2.1.

This matchup, from top to bottom, will be one to watch. The Storm boast four No. 1 draft picks to the Aces' three. The Aces lead the league in points per game in the regular season (90.1); the Storm were fifth at 82.5. The Storm had the third-best defensive rating; the Aces were sixth.

WNBA semifinals schedule

Game 1: Seattle at Las Vegas, 4 p.m. ET Sunday on ESPN

Game 2: Seattle at Las Vegas, 10 p.m. ET Aug. 31 on ESPN2

Game 3: Las Vegas at Seattle, 3 p.m. ET Sept. 4 on ABC

Game 4: Las Vegas at Seattle, TBD Sept. 6 on ESPN2*

Game 5: Seattle at Las Vegas, TBD Sept. 8 on ESPN2*

*—if necessary