The United States lead Japan 1-0 at the interval after an end-to-end 45 minutes in the Olympic women's final at Wembley Stadium.
It was the United States who created the first real chance after three minutes, but Alex Morgan's effort was palmed away by Miho Fukumoto.
The US did take the lead, however, five minutes later when Carli Lloyd turned home at the far post to send her side ahead.
The chances continued to fall for the US early in the opening period, and Lloyd again struck wide with 15 minutes on the clock.
Japan had a glorious chance to level moments later, but Nahomi Kawasumi and Yuki Ogimi were both denied with strikes from close range, before the latter struck the crossbar after 20 minutes.
Both sides continued to attack as the half entered its latter stages, and Aya Miyama rattled the crossbar for Japan after 32 minutes.
Japan ended the half the stronger as Ohno fired just wide of Hope Solo's goal, but it remained 1-0 to the US at the break.
