They led 16-0 at half-time against the Super League leaders on Thursday and looked set to earn a famous derby win at Belle Vue. Even though they then fell 18-16 behind they rallied again to lead once more only to eventually be undone by Luke Gale’s 79th-minute drop goal.
Walker admitted: “It is really gutting to lose like that. I can’t believe it really. We started so well, too well in some ways.
“They came out in the second half and we always knew momentum would change at some point, but it’s how you handle it.
“We didn’t handle it the best and Cas – who are a great side – thrived on it. But the way we opened gives us great encouragement. Some people might think we were on top for all of it, but we actually started dee-ing up quite a bit against Cas.
“We came against that adversity and we managed to get some points from it, kicking on to show how tough as a team we can be, both mentally and physically.”
Fifth-placed Wakefield head to lowly Widnes Vikings on Friday before rounding off their regular campaign at home to St Helens, the side Scotland international Walker left at the end of May.
They are just two points behind Salford Red Devils and Leeds Rhinos who play each other tomorrow, so their top-four hopes remain alive.
“That’s what we’re looking forward to – getting in that top four,” added the former Hull KR front-row. “We have a massive game next week and we need to win that. We have to keep pushing on and can’t let our heads go now.”
Walker, 26, is looking sharp having hardly played at Saints and then suffering a knee injury on his Trinity debut
He said: “That’s what I needed more than anything – consistency. Now my match fitness is coming I’m looking to get back to my best.”