Emily Sonnett celebrates after scoring her team's first goal against Costa Rica during the Concacaf W Championship. (Alfredo Lopez/Jam Media/Getty Images)

The U.S. women’s national team’s opening goal against Costa Rica came from an unlikely place, with Emily Sonnett notching her first international goal in the squad’s 3-0 Concacaf W Championship semifinal win Thursday.

The Washington Spirit defender put the USWNT up 1-0 in the 34th minute, breaking a stubborn deadlock by tapping in a loose ball following a corner kick from Mallory Pugh.

Thursday marked Sonnett’s 69th cap with the national team and her second consecutive start in the Concacaf tournament. Sonnett also played a crucial role in the team’s lone goal against Mexico on Monday.

The opening half was one of firsts, with Pugh following up Sonnett’s debut international goal with her first goal of the Concacaf W Championship. Pugh got on the end of a back-heel assist from Rose Lavelle, burying the finish to put the USWNT up 2-0.

Despite a series of big chances missed in the final third, the team went into the locker room with a pair of goals at the halftime break.

The latter 45 minutes were relatively quiet for the USWNT, but the squad logged a third goal in stoppage time. Ashley Sanchez inked her name on the scoresheet after Alex Morgan worked to bring down a lofted Kristie Mewis cross in the box, setting up the Spirit midfielder in front of goal.

The United States advances to Monday’s Concacaf W Championship final. The USWNT will face Canada, which took a 3-0 win against Jamaica in the other semifinal.