Great Britain have beaten Australia for the first time since 1988 in the first of two games at Olympic Park.
Sam Ward, Alistair Brogdon and Iain Lewers were all on the scoresheet in a 3-1 win, as the hosts surprised the World Cup-winning Kookaburras team.
Australia's Jamie Dwyer cancelled out Ward's early opener, but Brogdan and Lewers scored after the break to secure the victory.
GB head to Belgium next week for the World League semi-final.
They will play hosts Belgium in their opening pool game on 21 June before facing Ireland, China and Malaysia to complete the group phase of the competition, with a place in the World League final as well as Olympic qualification at stake.
"I'm very pleased with the result," said Great Britain head coach Bobby Crutchley. "There were periods of the game where we defended well but also periods of the game where we need to improve.
"We know Australia will get better as they come into the World League competition so although we are happy with the result today, we won't take anything for granted heading into the Olympic qualifiers."