Kyren Wilson should pinch this frame...

Talk about drama. Lei Peifan goes for a long red to the top left corner and leaves it.

The 21-year-old leads 60 points to 25 but the balls are in the open for Kyren Wilson to potentially make a counter clearance.

Oh my word. Lei Peifan goes for a red to the left middle and flukes it into the top left corner.

Kyren Wilson cannot believe it.

Kyren Wilson is shaking his head. He has missed a black off its spot while on 25.

Lei Peifan is at the table and cuts in a tough red to the bottom left corner.

What a chance this could be.

Kyren Wilson is suddenly starting to play like the reigning champion. He knocks in a long red to get going in 17th frame.

Kyren Wilson is closing in on a century break. This is a brilliant response from the defending champion...who clears the table.

Stephen Hendry
Seven-time world champion on BBC Four

This will give Kyren Wilson a massive boost of confidence and the encouragement he can go on and win this match.

Kyren Wilson is at the table and has already scored more points in this frame than the previous six combined.

Can he kick on from here and somehow still win this match?

Meanwhile, Hossein Vafaei looks like he has found his groove with a break of 123 to draw level.

That is seven frames on the spin for Lei Peifan, who compiles a break of 92 to move one frame away from a famous victory.

Stephen Hendry
Seven-time world champion on BBC Four

Kyren Wilson's defence of the world title looks to be in tatters at the moment. He will need to do something remarkable.

Kyren Wilson has been completely outplayed so far tonight. Lei Peifan is closing in on another frame.

Hossein Vafaei takes the fifth frame largely thanks to a run of 56. There has not been a great deal of tactical play in this match at all.

Lei Peifan plays the sort of frame where you'd need to drag him off the table.

Struggling early doors with positioning he knocks in pot after pot and enjoys a run of 59 to put the frame beyond Kyren Wilson, who is looking extremely perplexed.

Stephen Hendry
Seven-time world champion on BBC Four

You feel that if Kyren could get in and make a sizable break of 70 or 80 it would help settle him down.

Barry Hawkins and Hossein Vafaei aren't too far behind in going to grab a cup of tea.

The Englishman has established a healthy 3-1 lead and is simply making far fewer mistakes than his opponent.

Lei Peifan will not want to head to the mid-session interval.

He takes a fourth consecutive frame this evening to lead the defending champion with a brilliant break of 89.

Is the Crucible curse about to strike again?

Stephen Hendry
Seven-time world champion on BBC Four

If Kyren Wilson loses this frame he will have some battle to hold onto his title. It is just about getting the win now, even if it is ugly. He is going to have to scrap now.

Barry Hawkins edges back in front. Neither player is particularly hanging around this evening.

Lei Peifan crafts a lovely break of 75 and all of a sudden he is level and the defending world champion Kyren Wilson has serious work to do.