Reds led 10-6 midway through the first half but they were unable to keep up with the hosts after a three-try burst just before the break helped establish a 20-point buffer.
The Castleford stand-off had a hand in five of Castleford’s tries, and his partnership with Danny Orr is one of the key reasons behind the Tigers’ early season success.
Castleford coach Terry Matterson said: “Rangi’s playing as well as I’ve seen him play.
“That’s due to a whole lot of factors, but Danny Orr is certainly one of them. Rangi’s playing with a lot of control and he’s not over-playing.”
“We’ve worked hard on him being a team player and I couldn’t ask for anything more from him.”
Salford caretaker Steve Simms added: “Rangi was just outstanding. If there were any international teams picked this week, he’d get in all of them.”
Salford replied with quick-fire scores from Jodie Broughton and Vinnie Anderson that seemed to suggest they were capable of leaving Wheldon Road with two points.
But that was as good as it got for the Reds, whose off-field disruptions continue to dominate.
Shaun McRae has been on sick leave for six weeks, while assistant coach Malcolm Alker was also missing from Sunday’s match.
Simms explained: “It’s an in-house thing. We’ll be talking to Malcolm this week, but we’ll be keeping it between ourselves.”
Whether those issues are affecting Salford’s players or not, they need to start performing – and quickly. The Reds spent big in the off-season but their outlay has not been justified on this season’s performances.
Kirk Dixon, Richard Mathers, Arundel and Youngquest again went over in a 12-minute spell before half time that put the match out of Salford’s reach.
Castleford, chasing a 20-point winning margin to guarantee their place at the top of the table, appeared to be wobbling when Holdsworth went over at the start of the second half.
Adam Sidlow went over in the final minute for Salford, but there was no denying the fact they had been outclassed and at times embarrassed.