Styling first post differently in this particular loop

I have a loop that displays the recent posts for a custom post type, grouped by a custom taxonomy.

<?php
	$categories = get_terms('section', 'orderby=count&order=DESC&hide_empty=1&exclude=60,59');
	 foreach( $categories as $category ):
	 ?>
	 <h3><?php echo $category->name; // Prints the cat/taxonomy group title ?></h3>
	 <?php
	 $posts = get_posts(array(
	 'post_type' => 'knowledgebase',
	 'taxonomy' => $category->taxonomy,
	 'term' => $category->slug,
	 'nopaging' => true,
	 ));
	 foreach($posts as $post):
	 setup_postdata($post); //enables the_title(), the_content(), etc. without specifying a post ID
	 ?>
	 <div id="post-<?php the_ID(); ?>" <?php post_class(); ?>>

	 <div class="entry-content">
	 <?php the_title();?>
	 </div><!-- .entry-content -->

	 </div><!-- #post-## -->
	 <?php endforeach; ?>

	<?php endforeach; ?>

But how do I now take this and style the first of each post from each custom taxonomy differently? i.e. I want to show the excerpt of the first post, and just the titles of the rest…