Abby Wambach made it three wins out of three for reigning Olympic champions United States in this year's tournament with the defining moment of their narrow victory over North Korea.

Wambach scored her 141st goal in her 185th appearance for her country in front of a 29,522 crowd at Manchester United's Old Trafford.

It was enough to guarantee the United States top spot in Group G, and a quarter-final clash with New Zealand at St James' Park on Friday.

The first half was comprehensively one sided for Swedish coach Pia Sundhage's team against a North Korean outfit hammered 5-0 by France in their previous game.

The only surprise was that it took America until the 25th minute to break the deadlock, with goalkeeper O Chang-ran denying Megan Rapinoe and Alex Morgan, with the latter also striking the post.

The opener when it came was well crafted, with Carli Lloyd feeding Morgan in the area who turned inside her marker to lay the ball off for Wambach to beat O from seven yards.

Wambach later forced a third good save from O and also saw another effort hit the left-hand upright before the break.

Beyond that the second half was only notable for Choe Mi-gyong's 81st-minute dismissal for two yellow cards in five minutes.