Wales held on for a narrow 22-20 victory over South Africa in their Test in Washington.
First-half tries from Hallam Amos and debutant Tomas Williams - with Gareth Anscombe adding the extras - saw Wales come back to take a 14-3 half-time lead after trailing to an Elton Jantjies penalty.
South Africa hit back with tries from Travis Ismaiel and Makazole Mapimpi, either side of an Anscombe penalty.
But Robert du Preez's three-pointer saw the Springboks go back ahead seven minutes from time before Ryan Elias finished it off for Wales.
Steff Evans has been ruled out of Wales' summer tour to Argentina with a knee injury.
Evans was forced off during the win over South Africa in Washington and the Welsh Rugby Union has confirmed the player's worst fears have been realised.
The WRU said in a statement: "Steff suffered a knee injury against the Springboks which precludes him from taking any further part in the summer tour.
"He will return to Wales for further investigations to establish an accurate diagnosis and prognosis."
Worcester wing Josh Adams has been called up as replacement for Evans, while Tomas Francis has also joined the squad as cover for Samson Lee, who is battling a lower back injury.