It was seen as a most unlikely top-six clash at the start of the season but Castleford and Widnes have both proved their early-season sparkle was no fluke as they prepare to go head-to-head on Sunday.

Both clubs were tipped to be involved in the relegation scrap but t he Tigers have been a revelation in their first full season under Daryl Powell, winning nine of their first 13 matches, while the Vikings are only two points behind with a game in hand.

The game, which marks the halfway mark of the 2014 First Utility Super League, also pits two of the brightest English coaches against each other and Widnes boss Denis Betts is delighted at the impact made by his former Great Britain team-mate.

"It's good to see someone like Daryl, who has worked so hard, getting rewarded at that level and getting recognition he deserves," Betts said.

"He's built a very similar culture and ethical structure at Castleford now. I don't think they're going to fall over at all this year and will be fighting for the top four, semi-finals and finals.

"We're really looking forward to going there and having a tilt at them, because they're playing so well. People talk about our home ground but Castleford is a very formidable place to go. It's a different size of pitch, it's an imposing stadium and the fans are really behind them at the moment."

Castleford are boosted by the return of full-back Luke Dorn, who has missed the last six matches with a hamstring injury.

Warrington, the pre-season title favourites, are below both Widnes and Castleford but they produced their best performance of the season against St Helens last Sunday and will be confident of maintaining their dominance over Wakefield.

Tony Smith's men have won their last eight meetings with the Wildcats, whose last win over the Wolves was before the Smith era in the summer of 2009.

Wakefield, whose capacity at the Rapid Solicitors Stadium has been increased from 5,333 to 6,133, will give a debut to former Castleford winger Richard Owen after he was a spectator for their Magic Weekend defeat by his old club.

"Rich will give us a real boost this week," coach Richard Agar said. "We just thought that one training session and the occasion of playing against Castleford was a little bit too much for him.

"I t's important for him to try and get off on the right foot and we didn't want to put him under too much pressure straight away."

Hull KR coach Craig Sandercock has put his players on alert ahead of the visit of bottom club London Broncos, who have been inching ever closer to their first win of the season.

The Broncos pushed Huddersfield all the way in coach Joe Grima's first match in charge and Sandercock believes they were unfortunate not to break their duck against Catalan Dragons at the Magic Weekend.

"I've watched all their games and over the last month or so and they've been playing some really good rugby league," Sandercock said.

"They've got some continuity. They've kept the same side for the last month too and they probably deserved to beat Catalan on Saturday. We realise it's going to be a really tough game."

The return from injury of full-back Nesiasi Mataitonga and former Hull KR forward George Griffin leaves only winger Kieran Dixon on the sidelines and Grima is confident the club's first win is just around the corner.

"I think we're getting a bit of continuity," Grima said. "There's only one player that wasn't able to be selected so the medical and strength and conditioning staff have done a tremendous job in making it difficult for me to pick a side each week.

"The core group has been the same for the past three weeks and we can see the benefits. They are starting to understand each other's plays a lot more and we're working towards some goals in offence and defence. I'm really happy and excited that we've not had too many injuries."