Stephen Hendry only needed one frame to put the seal on champion John Higgins's worst World Championship defeat.
Resuming 12-4 ahead after taking seven out of eight frames in Friday's second session, the seven-time champion knocked in a 64 break to progress 13-4.
It was the 43-year-old's first ranking event win over his old practice partner since 2003, and secured his first Crucible quarter-final since 2009.
He faces fellow Scot Stephen Maguire, who sealed a 13-7 win over Joe Perry.
Hendry, who recorded a maximum 147 against Stuart Bingham in the first round, played down his prospects of going on to win an eighth world title - 13 years after his seventh - despite the run he has enjoyed so far.
"I wouldn't say two matches is a run, but I did win my qualifier as well so maybe that's three!" he told BBC Sport. "There is a long way to go but I am still in the tournament and I am very happy. Everything is a bonus for me at the moment. I have made a maximum, I have just beaten the defending champion and I've got Maguire next, so I can't wait.
"I am one match away from possibly being in a one-table situation at the Crucible again, which is amazing for me."
Both Higgins and Hendry played superbly during their opening session, in what was their first meeting at the Crucible despite 45 appearances (Hendry 27, Higgins 18) between them.
Hendry recovered from 2-0 down to level before Higgins knocked in a 124 clearance, but Hendry won the next three - including a sublime 123 - to lead 5-3.
When they resumed on Friday evening, Higgins missed the final black in the opener, and aside from winning a close 11th frame, presented Hendry with a host of opportunities with a catalogue of missed balls.
"It was one of the strangest sessions of snooker I have ever played in," Hendry said. "You hope to get one good chance in a frame, but I was getting five or six. I was coming to the table in shock because I couldn't believe the balls he was missing."
"It was really bad," concurred Higgins. "That second session was probably the worst I have played at the Crucible. I missed a chance to win the opening frame and from then on, it was torture."
Resuming 11-5 up on Saturday morning, world number seven Maguire saw Perry take the first two frames to reduce his deficit to four.
But Maguire, a Crucible semi-finalist in 2007, won the next before a break of 79 confirmed his place in a fourth World Championship quarter-final in six years, which will take place on Tuesday and Wednesday, 1/2 May.
The Scot led 5-3 after a high-quality first session featuring three consecutive century breaks - 116 from Perry, followed by two 101s from Maguire - in the opening three frames.
As Perry faltered in the second session, Maguire started to dominate with further runs of 91, 80 and 75 putting him in command, despite a second century from Perry in the 15th.
"I think I finished the match yesterday really by winning the second session 7-1," said Maguire, who believes he will need to up his game if he is make the last four for the second time.
"I must have stolen about six or seven frames off Joe, just like I did in the first round against Luca Brecel. That's good because it hurts the opponent, but I'm only getting in really because they're missing on 40 or 50, which isn't good enough.
"If I come up against players who are knocking in 70s or 80s, I'm not going to get any chances to clear up. I have to improve."
Welshman Ryan Day reeled off the four frames he required in quick succession to complete a 13-7 victory over Cao Yupeng.
The Chinese player, who upset Mark Allen in the first round, showed his battling qualities by taking five of the eight frames in Saturday morning's second session to trail only 9-7, having been 6-2 down at the outset.
Cao reeled off three frames in a row - featuring a superb 125 break in the 10th frame - to get to within one frame of Day at 6-5.
The former world number six, who has dropped to 35 in the rankings, responded with 112 before Cao won the longest frame of the match to make it 7-6.
Day then took the next two, aided by a run of 72, to make it 9-6 before Cao kept in touch by winning a tight final frame of the session.
But when they resumed on Saturday evening, Day kncoked in breaks of 113, 53 and 87 to progress to a quarter-final meeting with either compatriot Matthew Stevens or Barry Hawkins.