Selby is in charge in frame eight, as he has been for most of the last two hours. He has a lead of 41, but will probably have to go safe soon after losing position.

O'Sullivan has only gained 33 points since the end of the fourth frame. He desperately needs to get some quickly in this one or he will be 6-2 behind going into the evening's action.

Can there be anything worse for a player than to battle for more than 45 minutes trying to save a frame, only to go on and lose it?

That's what happened to Ronnie O'Sullivan in the sixth frame, and you can watch the key moments from that one in this clip.

Ken Doherty
1997 world champion on BBC Two

This is a massive frame for Ronnie O'Sullivan and his fans. Six-two would be a huge deficit to overcome in the evening session.

O'Sullivan is given a glimmer of hope and you get the feeling he needs this frame. But a rolled red stays just over the pocket, which Selby gets rid of to rip apart the seventh frame. Four in a row for Selby. O'Sullivan on the ropes.

OK, maybe not.

Selby is on a break of 58 and has a pink off the spot to deal with. But a moment of carelessness from the world champion, who puts too much juice on his shot. The pink stays out, crashes into most of the other balls on the table and the seventh frame is still alive.

The last frame took 45 minutes, Selby is making light work of the seventh and already has a break of 44 and is well placed for more. This should be a three-frame lead shortly.

Liam Glover: Poor frame that, nerves showing from both players.

Malcolm:  Big frame that, feel Ronnie needed to win it. @markjesterselby, external big favourite now, never rule Ronnie out but think its Selby's day.

Stephen Murphy: O'Sullivan's most difficult opponent has always been himself. 

Marc Bazeley: At this rate, the Masters will have started by the time this final finishes. 

We know how you feel, Marc. 

Dennis Taylor
1985 world champion on BBC Two

There are always some turning points in the best of 19 match, and one could be in the fourth frame when O'Sullivan could have gone 3-1 ahead. You pick out moments that turn matches.

Steve Davis
Six-time world champion on BBC Two

I suppose if you were to judge how you were going to become a good match player, it's how you deal with errors. 

Ronnie O' Sullivan is more fragile than Mark Selby when it comes to that area. 

But there is no reprieve for O'Sullivan. Selby pots the blue and leaves the pink hanging over the pocket to inch closer to the frame.

O'Sullivan hits the pink ball hard, to ensure it stays on the table, but the same cannot be said of the cue ball, which disappears into the opposite corner.

That frame, which took more than 45 minutes, is in the books and it is another for Selby. He was 2-1 down, but has won three on the bounce to lead 4-2.

Shamoon Hafez
BBC Sport at the York Barbican

Plenty of sighs and rolling of eyes as another frame ticks over the half an hour mark.

Some of these journalists have newspaper deadlines to meet, no such problem for those of us working for online publications.

You would expect Selby to win these battles but will be a great boost if O'Sullivan can pinch it.

Grind them down, force a mistake, come up with an excellent long pot.

That's what Selby does and then disposes of the yellow. But the blue on the side cushion means he has to go safe shortly after. Selby leads by 15, blue, pink and black on the table.

MR. W: If Ronnie doesn't start winning frames in 1 visit I don't fancy him winning this year's #UKChampionship., external

Muffin man: Notice how 90% of frames Selby plays, the table ends up awkward, to suit his tedious, slow, mundane play, he knows.  

Marc Bazely: Mark Selby is determined to try to win this final one gritty, hard-fought point at a time.

Where will this final be won or lost? Tweet us using #bbcsnooker.

Ken Doherty
1997 world champion on BBC Two

In these type of frames Ronnie is playing the best in the business. You have to be spot on against Mark Selby.

Some positional excellence from Mark Selby to get on to a red after screwing back after potting the green.

But even the best players can feel the pressure and Selby then misses a black. It is another epic frame. Who will win it? Selby leads 37-31 so far. Once again, for the second time this afternoon, the clock goes past the 30-minute mark for one frame.

Just what do you do you when faced with this table?

Matt Oswin: Big breaks are good, but I've always enjoyed a good tactical frame.

Jamie Saczak: Selby is the king of snooze snooker. Zzzzzzzz. Credit where credit is due, but just don't find it entertaining.

Jonesy:  Tactical frames that last no longer than 25 mins are fine, ones that last over 60 mins are not, did they put a timer on it?   

This snooker final is splitting opinion. What type of snooker would you like to see? Who has the advantage? Tweet us using #bbcsnooker and we will post your words of wisdom on this page. 

Ken Doherty
1997 world champion on BBC Two

Mark Selby is definitely testing Ronnie's patience at the moment.

So what's going on at the moment? Well, Selby leads by three points in the sixth frame, holding a 3-2 overall advantage.

Selby leaves a tempter for O'Sullivan, and the five-time world champion takes up the offer. The long red bounces around in the jaws of the pocket but stays on the cloth. Luckily for O'Sullivan there is no shot left on. As you were.

"It is getting a little bit nervy out there," says BBC commentator Dennis Taylor as Selby misses a black into the middle, which is immediately followed by O'Sullivan missing a red into the top corner.

Will Selby come from 25 points behind in frame six to open up a two-frame advantage? We will find out very soon.

This is the face you make when you have just missed what appears to be a straight-forward shot. Selby was aiming for the red on the left of the picture, missed it by a narrow margin and gifted some points to O'Sullivan.

Moments later O'Sullivan pots a red, the first ball we have seen sunk in more than 20 minutes of action.