An important combat principle to follow when fighting a Boxer is to stay your ground, and not to retreat when he makes an attack

When a Boxer jabs at you, you deflect his jabs away. When he strikes with crosses, you brush them away. Notice that in both cases, you work from outside in, following the momentum of his attacks. It is important not to retreat your feet, but use your body movement to avoid his attacks if they are close. Executed skillfully, you can control a Boxer effectively with just your left hand in deflecting and brushing away his attacks.