The girls in green are destined for a 9th-12th place play-off spot after conceding four tries to the powerful Americans.

Two tries inside 14 minutes from flanker Phaidra Knight and lock Erin Carter set the USA on the way to a 14-3 break lead.

Ireland threatened a comeback when Knight was sin-binned in the 52nd-minute and moments later prop Gillian McAllister plunged over for a try. But Knight wrapped up the win with her second try, eight minutes from time.

IRELAND: Joanne O'Sullivan; Jeanette Feighery, Lynne Cantwell, Grace Davitt, Amanda Greensmith; Sarahjane Belton (capt), Tania Rosser; Fiona Coghlan, Yvonne Nolan, Gillian McAllister, Caroline Mahon, Geramine Healy, Orla Brennan, Rachel Boyd, Joy Neville.

Replacements used: Jean Lonergan for Nolan (48 mins), Marie Barrett for McAllister (58), Eimear O'Sullivan for Brennan (63), Nuala Ni Chadhain for Belton (77), Rosie Foley for Healy (79). Not used: Louise Beamish, Shannon Houston.

Jean Lonergan, Marie Barrett, Rosie Foley, Eimear O'Sullivan, Louise Beamish, Nuala Ni Chadhain, Sam Houston.

USA: Ashley English; Ellie Karvoski, Patty Jervey, Hedwig Aerts, Pat Neder; Kristin Baja, Lee Knight; Annie Collier, Danielle Miller, Meredith Ottens, Erin Carter, Jen Crouse (capt), Kelly McMahon, Phaidra Knight, Kate Cox.

Replacements used: Jamie Burke for Ottens (half-time), Kate Pope for Carter (54), Laura Cabrera for English (60), Tina Nesberg for McMahon (66), Mari Wallace for Collier (69), Heather Hale for Neder (77). Not used: Claudia Braymer.

Referee: Christine Hanizet (France).