A 1-1 draw with Korea leaves Great Britain needing to win their last round-robin match and hoping other results go their way if they are to reach the final of the Sultan Azlan Shah Hockey Cup in Malaysia.
In humid, energy-sapping conditions, GB went behind in the 22nd minute when Yoon Sung Hoon wrong-footed Wimbledon defender Ben Hawes to fire in a shot which goalkeeper James Fair could not keep out.
Midway through the second half, Reading's Jonty Clarke smashed the equaliser past Myung Ho Lee from Ashley Jackson's pass.
Captain Barry Middleton was then denied by the Korea goalkeeper before Surbiton midfielder Richard Alexander blazed over when faced with an open goal, and Clarke had a shot tipped on to the post.
"It was a much better second half than first and I'm really pleased with the quality of play we managed to produce," said coach Jason Lee.
"The players gave absolutely everything and that was clear to see at the end of the game when many of them collapsed with fatigue."
Great Britain face bottom side Pakistan on Saturday needing a victory and most likely requiring Argentina to drop points against the hosts if they are to reach the final.