Forum:Question about Quick Play Cards

I'm a little confused about quick-play magic cards. Suppose I have a Magical Dimension in my hand, a Dark Magician on the field, and a Dark Magician of Chaos in my hand. Also, my opponent has a Vorse Raider on the field. Ok, I attack the Vorse Raider with my Dark Magician. The Vorse Raider is destroyed. Can I then play the Magical Dimension (I'm still in battle phase), tribute the Dark Magician for the Dark Magician of Chaos and attack my opponent? Or is this move illegal? I thought I could since it's a spell speed 2 magic card, but my opponent says I can't do that. Please let me know what the correct ruling is. I guess this ruling will also clear up the questions about other quick-play spell cards that I may have.