Penalty shoot-out defeat at Millwall.
John McGreal's men fell behind after fifteen minutes at The Den, as Jack Powell bent an unstoppable free kick into the top corner beyond James Bransgrove.
But the U's were level before half time as Tom Lapslie struck from just outside of the box after a neat one two.
The two teams traded chances throughout the game and either side could have claims to have run out winners in a energy sapping encounter.
The game was to go to penalties, though, and the first ten spot kick takers were successful in their efforts.
The unfortunate player on the night was Conor Hubble, who saw his penalty saved, before Millwall scored their sixth to edge a close match.