The 37-year-old back-row - the club's director of rugby - saluted his side after winning an attritional battle with Yorkshire League rivals Doncaster.
Cas were hot favourites to land the EDF Junior Vase after completing a Yorkshire Three double over Phoenix en route to a second successive promotion-winning season.


But in baking temperatures, Willett admitted his side struggled to produce their best and praised his players' desire and spirit in adverse circumstances.
"The conditions wer e horrific, the heat was relentless. It was too hit to sit out in, never mind run about in. We've gone from not having any hot games at all this year to unbelievable heat on Saturday.


"I'd have a shout as captain and then I was shattered from just shouting. I'd never experienced conditions like it and they had a massive effect on us.
"Doncaster were not the team we played twice this year. They had about six or seven players who I didn't recognise at all. However, we got the result and defended well.


"We've played every game since Christmas as a final, knowing that if we didn't win we wouldn't get promoted. That has been our motivation all along. We knew if we went out and did our best, they wouldn't be able to live with us. We didn't have our best game but what we did was effective and Lee Land had a blinder."
Man of the match Land scored Castleford's opening try and made the searing break that set up the match-winning touchdown for Jason Dunwell.


But it was no one-man show, insisted Willett: "It was a really good all-round effort. For me the forward of the day was Stuart Whybrow, who's been up there all year, and Gareth Paul also had a fine game.
"This is the culmination of a season-long effort. Everybody had to work hard in defence. Doncaster threw on a 20 stone prop they've got from somewhere, who always goes on for the last 20 minutes and scores a try.


"He did that again but we were good enough to keep him out after that to make sure our last score was enough to win it."
No-one can accuse Willett of letting the grass grow under his feet.
Just days after the club's memorable Twickenham success he was already switching his sights to next season - and a return to the home of English RU.


"We go into the Senior Vase next year but as far as we're concerned Wheatley Hills, who we will play in Yorkshire Two next season, made it into the Senior Vase final. If they can do it, we can do it.
"Our target is very simple, a hat-trick of promotions. We've got the team to do it. I've got my eyes on a bit of recruitment to strengthen areas where others are moving away or retiring but we only need a couple.


"I've talked to all the players about staying for another year and I don't think it will take too much. The attitude and atmosphere in our changing room prior to kick off on Saturday was unbelievable.
"You don't keep players without money changing hands if they don't enjoy being where they are - and no matter what anyone believes no-one gets paid at Cas.


"Everybody who comes wants to play in a team of good guys and that's what got us through the season."