Serena Williams sends ominous warning to her Wimbledon rivals

<div class="pa_art"><p>It was business as usual for Serena Williams as she went back to the day job and surged into the Wimbledon quarter-finals.</p><p>Andy Murray's doubles partner is a pretty handy singles player too, as demonstrated by a dominant victory over Carla Suarez Navarro.</p><p>Williams, who delighted Centre Court alongside Murray on Saturday evening, moved ominously closer to an eighth Wimbledon title with a 6-2 6-2 win.</p><p>The 37-year-old, sporting a child's plaster on her left elbow, never looked like coming unstuck against the world number 31.</p><!-- EMBED START Twitter --><figure><blockquote class="twitter-tweet" data-width="525" data-dnt="true"><p lang="en" dir="ltr">Serena Williams doing <a href="https://twitter.com . . .