Yea, it can be done with just a link. I have just checked me rankings for the made up phrase daseoexperiment and it turns out that I have top ranking over the page that gave me the link.
Now, since this is an experiment, let's see how further can I push the little authority this single link has given me. The fourth layer conquered with relative ease, it's time to step it up and go for that juicy third layer. Today's keyphrase is seo experiments for blogspot blogs!
See you when I get there, check back for the results.