Pagination with multiple loops in single.php using custom permalink structure

I feel this is fairly complex. This works perfectly inside a normal custom page template applied to a page but as soon as I put it into “single.php” the pagination no longer works. It redirects to the page itself and only displays the first page of posts tagged with ‘sports’.

My permalink structure is:
/%category%/%postname%/

but I don’t really want to change that. Any suggestions?

<?php
  $paged = (get_query_var('paged')) ? get_query_var('paged') : 1;
  $post_per_page = 2;
  $args=array(
    'tag' => 'sports',
    'paged' => $paged,
    'posts_per_page' => $post_per_page,
  );
  $temp = $wp_query;
  $wp_query = null;
  $wp_query = new WP_Query($args);
  if( have_posts() ) :
		while ($wp_query->have_posts()) : $wp_query->the_post(); ?>

            				<h3><?php the_title(); ?></h3>

	       <?php endwhile; ?>

    <div class="navigation">
      <div class="alignleft"><?php next_posts_link('« Older Entries') ?></div>
      <div class="alignright"><?php previous_posts_link('Newer Entries »') ?></div>
    </div>

  <?php else : ?>

		<h2 class="center">Nothing Found</h2>

	<?php endif;
	$wp_query = $temp;  //reset back to original query
?>

	</div>