SEATTLE — Erica Wheeler scored 17 points, including a go-ahead shot with 18.5 seconds left, and the Seattle Storm beat the Golden State Valkyries 74-73 on Tuesday night to secure the final WNBA playoff spot.

Seattle (23-21) clinched the 20th postseason appearance in franchise history.

After Wheeler’s pull-up jumper from the free-throw line, Janelle Salaun missed a shot in the lane but she got another chance following an offensive rebound. Salaun missed a corner 3-pointer and Wheeler secured the loose ball.

Nneka Ogwumike finished with 16 points and eight rebounds, Brittney Sykes scored 14 and Skylar Diggins had 10 points and six assists for Seattle. Wheeler was 5 of 7 on 3-pointers.

Salaun had 22 points and five 3-pointers for Golden State (23-20), which became the first expansion franchise to reach the playoffs in its inaugural season on Thursday. Temi Fagbenle scored 14 points and Veronica Burton had 14 points and 11 assists. Kaila Charles added 12 points and nine rebounds.

Golden State went on a 13-0 run — started by three straight 3-pointers by Salaun and Monique Billings — to take a 60-50 lead late in the third quarter. The Valkyries were 4 of 4 from distance in the third before missing their first six of the fourth.

Seattle scored the opening 10 points of the fourth, capped by a 3-pointer by Wheeler, to take a 63-61 lead.