Ulster manufactured two more penalties, with Carr the guilty party on both occasions. Replacement O'Connor landed the first from long range, but his second strike faded to the right and wide.
It looked like Brian McLaughlin's men would hold on to register their fourth straight win of the campaign.
Keatley had other ideas, however, and his composed 40-metre kick reeled Ulster back in for the final time, with the visitors' last scoring opportunity a hurried drop goal attempt from O'Connor.
|Connacht Rugby Score Card|
|Ulster Rugby Score Card|