Ding Junhui the provisional world number, won the first of the evening against Shaun Murphy the 2005 champion.
He looked sharp when knocking in a fluent 58 break, but didn't clinch the frame until potting the blue, as Murphy battled.
The Chinese star looked certain to open a two frame advantage until missing a routine red, allowing Murphy to counter with 31 to level the tie once more.
Junhui exploded into the potting machine everybody is used to seeing in the next. An effortless total clearance of 137. It was his third century in this event and increased the Crucible total to 43.
Again Murphy replied to restore parity with runs of 36 and 25 either side of a 51 break from this seasons UK Championship winner.On the stage of his greatest triumph, Murphy then went into the lead for the first time since the opening frame of this Betfred.com World Championship second round tie.
In a high quality encounter, one of the players had to show some weakness or lapse of concentration. It was Junhui to be that player, missing balls he would normally slot home.
Murphy appeared to increase the tempo of his game, almost smelling blood knowing the match was there for him to take.Junhui made him battle hard in the frame 22, but could not stop the Englishman extending his lead to two.
Now within touching distance of the winning line 12-10.Murphy seized his chance immediately in the next to seal the match.
After Junhui, missed a red to the centre pocket when trying to gain prime position for the black.
Murphy looking totally at ease, he finished the match off in superb style. A fourteen red clearance of 128 booked his place in the last eight, and again halted Junhui progress beyond the second round at the Crucible.
The win for Murphy sets up a tie with world number five Allister Carter, which starts 2:30pm Tuesday.
Shaun Murphy comments.
Very pleased, over the moon to win. There was a time in my career a few seasons ago when I played Ding and I came out on top. That changed and the last few times he's won but here at the biggest tournament I'm glad to have won.
I remember Ding when he first came over to the UK when I used to live in Northants and he came to the club, he was about 15 and he was special then so to see how he's developed is quite a privilege for me as he's developed into one of the best players in the world.
When we came out for the match I was up for it so I was disappointed to finish 5-3 but having come back before from a lot further behind in matches in this tournament it's the first to 13 not five.
I'm a firm believer in that it's not over until you've shook the guys hand. I've seen other people this week, their heads go down if the balls don't go their way but you have to press on and never give up.
Well there's massive expectation on his shoulders, the poor lad where ever he goes. I've played in China and seen the expectation that follows Ding around it's slightly unfair on somebody so young when he's trying to do well for himself and his country.I think they need to give him a break and let him develop.
This is where the rubber hits the road. The eight players that are left are probably the best eight in the game at the minute and very excited to be among those eight. Last time Ali played me here he came out on top so I'll be looking to turn the tables.
Ding Junhui comments.
It was a long match, I lost my feeling and concentration.
I am disappointed but I've been doing well this year, and will take a lot of experience from this match.
I missed some shots, but I played the right shots eeven if if I did miss them.
It would be nice to win this one year but there is many players who have not won it, so I wil keep trying and practicing.
Shaun tried very hard in the match, and is a tough player to play against.
He can win the tournament because he has won it before.