A late penalty by USA fly half Kimber Rozier proved the difference as Wales fell to a 7-10 defeat in their 2014 World Cup warm-up match at Pandy Park in Cross Keys.
Both sides scored one converted try apiece with winger Vanesha McGee ploughing over for USA and No 8 Sioned Harries replying in the second half for Wales.
Both sides ignored the wind and rain to play an open game of rugby with McGee and full back Akilaini Baravilala a constant threat with ball in hand for USA while Dyddgu Hywel and Laurie Harries featured regularly in counter attacks for Wales.
The teams were deadlocked until the 39th minute when USA ran the ball right and McGee dived over to score a well-executed try despite the best efforts of Harries and Hywel in defence. Rozier landed an excellent conversion to give the Americans a hard fought 7-0 lead at the interval.
Wales got back in to the game in the early stages of the second half through their forwards with Caryl Thomas and Catrin Edwards willing workhorses.
Wales got back on level terms in the 60th minute after holding onto possession for several phases. The ball was spread wide where Sioned Harries was lurking with intent and the speedy No 8 showed a clean pair of heels as she cut back against the grain to score under the posts. Laurie Harries added the extras to bring the scores level at 7-7.
Wales continued to attack but were guilty of coughing up possession at crucial times. USA made them pay by bursting downfield to set up Rozier for a penalty after Welsh forwards were penalised for coming in at the side of a ruck. The fly half had no trouble striking the ball between the uprights to edge her side back in front.
Wales finished the match in the ascendency but couldn't find a way through as USA held out for a gritty win.
Despite the narrow defeat, Wales Women's head coach Rhys Edwards was satisfied with his team's efforts.
"Going into the game we didn't know much about them but we knew it was going to be a tough game, especially as they are ranked in the top five teams of the world. The scoreboard doesn't really reflect that so I'm pretty pleased with the performance.
"We created some chances against one of the best teams in the world - the difference being when they get a chance they score, we don't. We take two, three, four or five times to get on the score board. We've got to show some composure and a bit of belief but we are certainly knocking on the door.
"We are improving and we showed that today. As we look ahead to the World Cup, we have another game against Ireland and there is no reason why we can't kick on from there and challenge in France."
Forwards coach Robyn McBryde says tomorrow's RBS 6 Nations clash against Italy gives Wales an opportunity to finish second in the tournament after having the wind knocked from their sails last week against England.
Wales head coach Warren Gatland tells WRU TV that his selection for the final clash of the RBS 6 Nations against Italy is an opportunity for some players to redeem themselves after Saturday's loss to England
Wales Women's head coach Rhys Edwards believes his side is back on track in terms of objectives and is confident his side can emulate last year's achievement by beating England for a second consecutive year on Saturday.
Wales head coach Warren Gatland is expecting 'one heck of a game' when his side tackle England at Twickenham on Saturday in the RBS 6 Nations. He believes whoever wins the game, could go on to win the championship.
Judgment Day IV had broken every attendance record in the history of Welsh domestic rugby before a ball had been kicked at Principality Stadium today and Welsh Rugby Union chairman Gareth Davies had two things to say to the 68,262 supporters who turned up to show their allegiance to their national sport - 'thank you' and 'please come back soon'.
A bitterly disappointed Wales head coach Gareth Williams was left scratching his head at his team's abject performances in the Singapore Sevens which culminated in an 'awful' display against Russia in the Bowl final.
Wales duo Rhun Williams and Liam Belcher, who makes a welcome return after five months of injury woe, look ahead to next month's World Rugby U20 Championship in Manchester where they will face Ireland, Georgia and New Zealand.
The pressure is off and the Welsh Women's team hope to end their Six Nations Championship on a high by recording a third win when they host Italy at the Talbot Athletic Ground, Aberavon on Sunday (2.00pm).