How to properly download the following plugin video? After nearly a week browsing all over the web, using Safari 5.1.10 Develop menu, Activity Monitor, etc…, how can I download the following video to my Mac:

http://screengrabber.deadspin.com/messi-opens-copa-del-rey-final-scoring-with-marvelous-g-1707941937

I can't find the video's URL to download on Safari activity monitor nor web inspector.
Right-click on the video and select Inspect Element.
Click the disclosure triangle next to the video element to reveal the source element.
Click the src attribute value to download the video.