The gifted Australian full-back scored a hat-trick of tries in the record-breaking 52-12 win, his first game in two months after being on the sidelines with a hamstring tear.
However, just hours later, Dorn announced that he would soon be calling time on a career that has largely been spent in the UK, having joined London Broncos originally in 2005.
The former Manly Sea Eagles, Sydney Roosters and Salford City Reds player – he operated mainly as a stand-off before switching to No 1 latterly – will be 34 in July but looked as sharp as ever when destroying Leeds.
“It will be with a heavy heart when I finish here, but I’m really excited that my last game will be for this great club,” Dorn said in a statement released to general surprise yesterday.
“It’s a completely different club from when I was here the first time (he returned in 2014 after a solitary season with Castleford in 2008), and I think we have all played a part in where the club is at now.
“I’ll be leaving this club in a good place.”
Last season Dorn made his 250th club appearance in the UK, a record for an overseas player, and he was instantly back in the action during his latest game at Leeds.
Castleford captain Luke Gale was outstanding at Headingley, too, producing an all-round masterclass at scrum-half, and setting up so many of the visitors’ tries.
Talking about the 27-year-old, Dorn admitted: “He’s fantastic. I love playing with Galey.
“When they brought him down to London (2009-11) we had a really good relationship there.
“Although we didn’t win as many games as we did when we came to Cas we still played some good stuff.
“We’ve always had a good understanding between and can play pretty hot at times and do things off the cuff.
“He’s just been outstanding for us and he’s started to learn the other side of playing scrum-half now.
“He just looks like a free spirit who does what he wants but now he’s also got control.
“Any half-back worth his salt will develop that and he’s started to get that.
“It’s turning him into a great half-back.”