Murphy, who was edged out by Robert Milkins on Sunday, got back on track straight away as breaks of 72 and 75 helped him establish a three-frame lead.
Murphy extended his early advantage to 5-1 and despite Selby taking the next two frames to reduce the deficit, the 40-year-old eventually nudged over the line.
— World Snooker Tour (@WeAreWST) February 21, 2023
Murphy told World Snooker Tour: “I’m very happy. The result on Sunday against Robert had a huge impact on the draw.
“I then had to face one of the hardest players in the tournament and one of the hardest players of my career.
“I certainly know that he has had the better of me more times than the other way round. We’ve been playing each other since we were 10 years of age and we know each other very well on and off the table.”
Meanwhile Milkins continued his own remarkable momentum by claiming a 6-5 win over Tom Ford, taking victory with a break of 74 in the decider.
Earlier, Kyren Wilson eased in the quarter-finals with a 6-2 win over China’s Zhou Yuelong.