Matt Murphy has had a pretty darn significant influence on blues guitar.
Going back to the '50s, he was Memphis Slim's guitarist, providing a great counterpoint to Slim's piano. One of the songs on John Mayall & the Bluesbreakers with Eric Clapton (the Beano album) is a Memphis Slim instrumental called "Steppin' Out." Even before that with the Yardbirds, Clapton takes a short but powerful solo in the song "I Ain't Got You." The solo is very similar to a solo done by Murphy in another Memphis Slim song called "Lonesome."
We know Freddie King was a huge influence on Clapton, but he had to be listening to Matt Murphy as well, whose playing style bore similarities to King's.
Now for something amazingly cool, check out "Memphis Slim & Matt Murphy - Matt's Guitar Blues" from 1963 on youtube. And also on youtube, live w/Slim from '63: "Matt's Guitar Boogie." Great stuff!