Murphy, who won the tournament in 2008, raced to a 3-0 lead at the York Barbican after making impressive breaks of 51, 55 and 114 before his opponent managed to stop the rot in the fourth frame.
However, that proved to be the only positive of the match for 'The Walnut' as his fellow Englishman won the next three frames, easing to a 6-1 victory and booking his place in the last-eight.
Speaking after the match, 'The Magician' said: "On another day it could have been closer. It was a bit tighter than the score suggests. I picked up a few of his crumbs. He had chances and didn't take them."
Murphy will now go up against King in the quarter-finals, after 'The Romford Battler' produced a gutsy performance to beat Scotland's John Higgins in the fourth round.
Elsewhere, Martin Gould was able to overcome China's Xiao Guodong 6-4 in a scrappy affair and the world number 18 was just happy to advance to the next stage of the tournament.
"Sometimes you have to win ugly," he said. "Neither of us has played as well as we can but I am through and that's what counts."