Rapinoe's OL Reign reached the National Women's Soccer League (NWSL) final on Sunday with a 1-0 victory over the San Diego Wave.
Veronica Latsko's 47th-minute goal was enough for the Reign in their semi-final clash and means Rapinoe will be back for one more match when her Seattle-based club face Gotham FC for the title in the same Snapdragon Stadium in San Diego next Saturday.
Rapinoe, celebrated for off-field activism as well as her success on the pitch, announced earlier this year it would be her final season.
She ended her epic US national team career with 63 goals in 203 caps over more than 17 years in September in a farewell match at Chicago's Soldier Field.
Next week, she'll be gunning for a trophy she has never won when the Reign take on Gotham FC -- who ousted reigning champions Portland with a 1-0 victory after extra time earlier Sunday.
The championship match will also be the final career game for Gotham's Ali Krieger, a two-time World Cup winner with the USA.
