After successive defeats to Poland and the Netherlands, Britain knew another loss would virtually end their hopes.

It was a clinical Tom Bertram penalty corner seconds before half-time that separated the teams.

But GB were far from convincing in the second half, with Japan seemingly unlucky to have a goal disallowed.

Despite looking understandably nervous, Britain had plenty of chances to make the win more comfortable but always looked vulnerable to a Japanese breakaway.

In the end it was down to true British grit Jason Lee, GB coach

Surbiton defender Ben Hawes hit the post with a low flick from a penalty corner in the 24th minute and had another saved by the impressive Takahashi.

However, seconds after Bertram gave GB the lead, Japan went within inches of claiming a shock equaliser.

Danny Hall wasted a good chance to wrap up the match in the 56th minute when clean through on goal, and in the closing stages Britain were simply happy to play down the clock.

"Thank God," said coach Jason Lee.

"The tension on the bench was incredible and it got worse and worse, especially when we kept missing chances on a regular basis.

"We can take confidence from the result of this game today, although in the end it was down to true British grit."

Lee knows further improvement is needed when his side take on European silver medalists Spain on Sunday.