Russell Martin admits Swansea City lacked the ruthlessness and energy needed to kill off Bristol City in the FA Cup meeting between the sides.
The Swans dominated the opening half of the third round contest at Ashton Gate and went ahead through what was Joel Piroe's ninth goal of the season in the 15th minute.
However, the visitors' energy levels dropped after the restart, and Antoine Semenyo headed home on 75 minutes to earn the Robins a replay.