They didn't shoot them down by dog fighting though they'd get to range and keep as much distance as possible they were never as manoeuverable as the defender but that didn't matter because the missiles were and could chase them effectively.
The defender went 155 the gun boat went around 80 and turned like a pig in a dog fight it loses at range firing multiple missiles it wins.
Also if your gonna insult someone's statement you need to explain why you think their wrong or you coming across as having no real argument and that does you no favours.