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Video - Late winner for GB's women
Great Britain's women rescued their Olympic dream with a last-gasp Crista Cullen penalty corner to beat Japan 2-1 in their penultimate group game.
Cullen's winner, with 20 seconds left, means GB could reach the semi-finals if they beat the US on Monday.
World number one the Netherlands beat Australia 2-1 in their fourth straight win in pool A to become the first team to make the final four.
Australia are tied in second place with hosts China, who beat South Korea 6-1.
China and Australia play a crucial match on Monday to see which of them progress to the semi-finals.
In other games, the USA won their first game of the competition against New Zealand 4-1, Argentina broke Germany's unbeaten streak with a 4-0 victory and Spain beat South Africa 1-0.
GB need to make the top two of Pool B to progress, but currently lie third behind Germany and Argentina.
The Germans have nine points with Argentina on eight, and the British third on seven.
But the Argentines' goal difference is vastly superior to Britain's, so GB need to beat the US and then hope either winless bottom team New Zealand hold Argentina, or Japan beat Germany.