A big mistake from Jamie Shaul, as he knocks on to hand possession back to Castleford deep inside Hull territory.

Tigers get within two metres on first tackle.

Jesse Sene-Lefao is penalised for a high challenge on Hull forward Mark Minichiello, and the hosts once again opt to kick the points.

Jake Connor stays perfect with his kicks to extend the lead to four points.

Hull FC get the second half started.

Who will become the fourth and final team into the Challenge Cup semi-finals?

Keep sending your tweets using the hashtag #bbcrl.

A reminder that the draw for the Challenge Cup semi-finals is coming up on straight after the conclusion of this game.

You can follow the draw right here by keeping watching the BBC Two stream after the game has finished, and I'll be sticking around a little longer for those of you who can't watch the match.

Now you may be out in the garden while following the live text, sweating away as you just sit there.

So spare a thought for the guys out there today. This is what they have to deal with.

Image source, bbc

Castleford captain Michael Shenton was just on BBC Two a moment ago and he revealed the ball was greasy in the sunshine, which may explain why we've seen so many handling errors in the first half.

Castleford captain Michael Shenton on BBC Two:

"That was an atrocious start from us, but we ground our way back in it.

"We need to tidy up our game, keep completing sets and put Hull under pressure."

That was a brilliant half of rugby league.

Hull FC were slightly the better side for much of the game, but two moments of magic from Ben Roberts and Luke Gale have kept Castleford in with a chance of reaching the semi-finals.

The drop-out eventually results in a penalty being awarded to Hull, and Jake Connor opts to kick for goal.

The kick is good, and Hull have a slender lead once again.

Hull FC were well on top for the first 25 minutes, but Castleford have shown the quality that has taken them to the top of Super League to tie things up.

Greg Minikin comes up with an error for the Tigers though, spilling a high-kick out over the dead-ball line for a goal-line drop-out.

We saw this yesterday from Wigan, and now it's Hull FC's turn to kick the ball out on the full from the restart.

Tigers are pressing to level the scores now.

So close for Castleford!

Greg Eden tries to bring in a pass with one hand with a clear run to the line ahead, but he can't quite bring the ball under control.

The visitors are starting to ask a few questions of Hull's defence after an uncharacteristically poor start.

Image source, SWpix.com

Just for a moment, Castleford look like they might break through the Hull FC line as they flip the ball quickly out to the left.

As soon as the gap is there though, another handling error hands possession back to their opponents, as Michael Shenton can't cling onto a pass.

Danny Washbrook is held up over the line as Hull FC continue to put the pressure on.

Castleford hold firm this time, as a well-timed tackle on Mark Minichiello jars the ball loose.

Castleford's vaunted attacking game hasn't posed Hull too many problems so far.

The hosts are dominating for territory, helped by a string of Tigers penalties.

Another penalty, this time for leaving a foot in the ruck, gives Hull another opportunity to test the Castleford defence.

So close for Hull FC again!

Albert Kelly tries to dart through a gap for the third try, but he knocks the ball on as he tries to spin and dive for the line.

Castleford look a little rattled here.

How do the Super League leaders respond from here?

Castleford are packed with quality, but an intercepted pass and a missed tackle on Fetuli Talanoa have them firmly on the back foot early on.

A Tigers penalty gives the hosts another chance to start an attack from inside opposition territory.

Daniel Smith: Quality interception by Hull. Going to be a good game this.

We really hope you're right, Daniel.