Murphy pulled one back with an impressive break of 104, and looked like mounting a comeback in the sixth frame after putting together a run of 64, but the Magician missed an easy pink and gifted the frame and the match to his illustrious opponent.
Ronnie O’Sullivan: I’d rather get smashed 5-0 than risk a long match
"I missed a lot of balls, he had a lot of chances, but he didn't take them," said O'Sullivan.
I'm not prepared to grind it out, I'd rather get smashed 5-0 or smash someone 5-0. I couldn't do what Selby did today [try and overturn a deficit], I don't want it that bad.
O'Sullivan goes on to face Joe Perry, who won four frames in a row to come back from 3-1 down to beat Alexander Ursenbacher 5-3, hitting breaks of 67, 73, 95 and 73 on his way to the semi-finals.
Defending champion Judd Trump was also in irrepressible form and continued unabated with a 5-1 against Anthony Hamilton.
The world champion put together runs of 106, 66, 73 and 105 to set up a semi-final showdown with John Higgins.
Despite the comprehension nature of the scoreline, Hamilton, the 2017 German Masters winner, had his chances, namely in frame two where a loose safety allowed Trump in to dispatch the pink to open a two-frame lead.
Hamilton, 48, briefly stemmed the tide, taking frame three but had no answer for Trump’s superior shot-making, who rattled off the next three frames on the bounce to progress.
"It's quite tough playing Anthony, it's hard work," said Trump.
Glad to get it over and done with quite quick, just starting to feel tired the last few days. Luckily, I'm getting through quite easily. I just didn't quite feel it out there today.
Trump goes on to play Higgins, who beat Mark Selby 5-4 in an absolutely thrilling quarter-final, denying Selby the chance of a Home Nations sweep and a £1 million bonus - although the match was most memorable for Selby taking over six minutes to take a shot in the seventh frame.
Mark Selby takes six minutes and 13 seconds to take a shot
Higgins ground out an error-strewn first frame but Selby hit back with a run of 101 to equalise. But Higgins capitalised on a number of Selby mistakes and put together runs of 65 and 67 on his way to opening up a 4-1 lead.
But with the semi-finals in sight, Higgins botched a routine black and let Selby back in, and the Jester reeled off breaks of 102, 62 and 52 to level the match.
Selby took control of the table but this time he blundered, making a mess of a plant on a red leaving the table open and Higgins made no mistake, cleaning up with a break of 110 to take the match.
‘Maybe his mind went to mush’ – Higgins on waiting for Selby