St Helens made their numerical advantage tell, with the Red Devils down to 12 men after Ryan Lannon was red carded for a high, late challenge on Theo Fages on 37 minutes.
Salford were holding their own against their title-chasing visitors until they were reduced to 12 men with the sending-off of forward Lannon and the numerical disadvantage proved too big a handicap as they went down 30-4 at the AJ Bell Stadium.
Salford coach Ian Watson had no complaints over the dismissal of Lannon but argued that St Helens player Alex Walmsley should have been shown a yellow card for the use of his elbow in a tackle on Jordan Walne.
“It’s a young kid getting frustrated,” Watson said.
“Maybe if there had been a sin-binning on the back of the elbow he might not have done it.
“It was a silly, dumb error, but he’ll learn from that.”
Click on the video above to view the dismissal