User blog comment:MOTZI/Think About It - Marksman's fate/@comment-8802138-20140323113012/@comment-5649293-20140323225634

Yea also it depends if the mage is an AP Nuker aka  then in this situation sustain would help you survive (by getting some lifesteal for her or nearby minions) if her combo let you with like 5% hp left since the major weakness of AP Nukers are cooldowns right after they use their combos.