After the hosts had applied virtually all the pressure without breaking the deadlock - Mark Davies going the closest - it was the Swans who went 1-0 up in the 43rd minute through Luke Moore's deft chip.
But Pratley, who left the Welsh side for Bolton in the summer, squared things by heading home an equaliser in first-half stoppage time before Chris Eagles settled the fourth-round tie 11 minutes after the break, reacting when Gerhard Tremmel could not hold on to Martin Petrov's strike.
Source: PA
Source: PA