Cook launched a speculative ball into the box which goalkeeper Courtney Brosnan, who was badly positioned, could not prevent from going in.

The US had beaten Ireland 2-0 in the first of two meetings on Saturday.

In that match, striker Mallory Swanson tore a patellar tendon in her left knee, an injury which is likely to keep her out of their defence of the World Cup.

Ireland, who play hosts Australia in their opening World Cup match on July 20, had created opportunities in St Louis before falling behind.

Lucy Quinn twice had a chance from Katie McCabe crosses but, after falling behind, they rarely looked like getting back on terms.

Defender Becky Sauerbrunn came close to a first international goal on her 216th appearance for the US when she hit the crossbar, having been honoured in a ceremony in her hometown for passing 200 caps.