Breanna Stewart had 21 points, 10 rebounds and eight assists, Sue Bird added season highs of 18 points and 10 assists, and the Seattle Storm beat the Washington Mystics 97-84 on Sunday to sweep their opening-round series.

No. 4 seed Seattle plays top-seeded Las Vegas in the second round. The best-of-five series begins next Sunday in Las Vegas.

Jewell Loyd was 5 of 10 from 3-point range and finished with 19 points for the Storm. Gabby Williams, who suffered a concussion in the third quarter and did not return, scored 14 points and Tina Charles added 10.

Ariel Atkins hit a 3-pointer 13 seconds into the third quarter to give the Mystics a 46-45 lead, but Stewart answered with a 3 on the other end and Seattle never again trailed. Stewart made a fade-away jumper to stretch the Storm’s lead to 17 points with 6 minutes to play.

Natasha Cloud made 5 of 8 from 3-point range and finished with 21 points for Washington. Atkins added 15 points and seven assists, Elena Delle Donne and Shatori Walker-Kimbrough scored 12 points apiece, and Alysha Clark 10.

The Storm made 35 of 63 (55.6%) from the field, shot 52.2% (12 of 23) from 3-point range. finished with 27 assists and committed a season-low eight turnovers.