Murphy revealed he had been on the verge of withdrawing from their second round clash following a flare-up of a condition he has endured for much of his career.
But the 40-year-old defied the "complete agony" of their four-hour showdown in style as he reeled off three centuries and won the last three frames for a 6-5 win and a place in the quarter-finals.
"I think when the dust settles and I think about where that match fits into my life, given all the various contexts, it will probably be up there," said Murphy, who had tweeted that he was in "terrible pain" two hours before their match was due to start.
"I played pretty much 95 per cent of my shots in complete agony. I reached and stretched for some shots I shouldn't have done, and I'm sure that will come back to get me.
"I have one of those massage guns but in my haste to bring as many suits as I could, I forgot to bring it. My friend Robbie and I dashed to the shops this morning trying to find one.
"We got a taxi back to the hotel and had half an hour with it. I could barely bend down in my practice session last night and it lasted five minutes. It's very painful but it was either quit or try, and I chose to try."
Stocked up with "as many painkillers as I'm allowed" and showing no apparent ill-effects from his injury, Murphy won two of the first three frames of the match, including a century in the opener.
Trump won the next two, taking advantage of a botched safety on the green by Murphy to nudge ahead, then survived a simple missed red in the next, rallying with a 62 clearance to extend his lead to 4-2.
Murphy hauled his way back within one frame after winning an extended safety battle in the seventh, but once again failed to punish Trump for a missed blue off the spot in the next as the world number three moved within one frame of victory.
Murphy responded with back-to-back centuries - a 110 to brown, followed by a valiant attempt at a maximum that petered out after 13 reds and blacks - to force the decider.
Murphy got in first with a break of 44 and after Trump missed a golden opportunity by leaving a long red in the jaws, Murphy returned to the table to polish off a further break of 53 and wrap up victory.
Trump, who admitted this week that his record since his solitary win at the tournament in 2011 was "atrocious", appeared surprised by Murphy's ability to shrug off his injury.
"He knows if he was injured or not," said Trump. "You can't play like that with an injury. The way he started off with a century in the first frame put all doubts to bed.
"He was involved out there and he certainly played like he wasn't injured. If he was injured, maybe he should stay injured."
Three-time winner Ding Junhui recorded six half-centuries, including a 118 in the fourth frame, as he reached the last eight with a 6-1 win over Welshman Jamie Clarke.
Ding will face seven-time world champion Ronnie O'Sullivan in the quarter-finals, while Murphy will take on Jack Lisowski following the left-hander's 6-2 win over Hossein Vafaei.
Joe Perry will face Tom Ford in the last eight after beating Stuart Bingham 6-3. Bingham made two centuries but Perry scored heavily throughout with contributions of 93, 82 (twice), 75 and 64.