Skipper Elinor Snowsill landed an 11th minute penalty to give Wales a 3-0 lead at the break. Dogged defence ensured Wales held their slender lead until the 79th minute when USA winger Tyra McGrady scooped up a loose pass to run the length of the field to give Catherine Parkhill an easy conversion to give the USA a 7-3 victory.
The defeat will be a bitter pill to swallow as Wales were always in control of the game but an inability to convert pressure into points came back to haunt them.
Lowri Harries and Vicky Owens were prominent up front in the early stages while the centre partnership of Adi Taviner and Ceri Redman also showed up well.
USA were penalised for failing to roll away after making a tackle and Snowsill sent the ball between the uprights to give Wales an early and justified lead.
Wales continued to take the game to USA with Snowsill pulling the strings from fly half. Sioned Harries, Snowsill and Taviner along with Charlie Murray kept the American defence honest but Wales were unable to cross the white-wash.
USA’s Erica Cavanaugh was sent to the sin bin in the 58th minute with a high tackle on Rhianydd Morgan but Wales were unable to capitalise while the winger was cooling her heals.
Wales had looked to have done enough to get their campaign off to a winning start but disaster struck in the last minute of play. All Wales had to do was kick the ball dead from a penalty, but with the clock ticking down a quick tap was taken deep into USA territory. The ball was dropped and McGrady pick pocketed the ball to dash unhindered to the try-line to break Welsh hearts.
Wales will now have to pick themselves up in preparation for their next game, against Canada on Sunday. (KO 1.30pm).