Yes, Vasto Lorde is stronger than average captain but there are also few important factors here at work. First: Tia's attack's are all water based so Hitsugaya's ice attack's have advantage. Second: Hitsugaya was still at disadvantage but he didn't want to use his most powerful attack because he was afraid that he couldn't control it. He decided to take the risk and use it. Hitsugaya froze Tia but before she was destroyed Wondervice saved her. Third: She was affected by that attack and before she could regain her self two former vice-captains(vizard Hiyori and Lisa) appeared. 3 to 1 is clear disadvantage.Not necessarily. All Vasto Lordes are not stronger then all captains.