WordPress menu item selective customization

I have a WordPress menu / wp_nav_menu setup like this:

<ul>
  <li><a href="">Link 1</a></li>
  <li><a href="">Link 2</a>
    <ul>
        <li><a href="">Sub-link A</a></li>
        <li><a href="">Sub-link B</a></li>
        <li><a href="">Sub-link C</a></li>
    </ul>
  </li>
  <li><a href="">Link 3</a></li>
</ul>

All I want is to change the structure of Link 2 from:

    <li><a href="">Link 2</a>
      <ul>
        <li><a href="">Sub-link A</a></li>
        <li><a href="">Sub-link B</a></li>
        <li><a href="">Sub-link C</a></li>
      </ul>
    </li>

To be like:

    <li><span>Link 2</span>
      <ul>
        <li><a href="">Sub-link A</a></li>
        <li><a href="">Sub-link B</a></li>
        <li><a href="">Sub-link C</a></li>
      </ul>
    </li>

Basically I want the second menu item not to be a link instead a span, rest of the structure remains the same. Is there a way we can target specific menu item?