Hull trailed 20-18 until the Great Britain winger touched down after Richard Horne?s kick was tapped back by Sid Domic.
The touchdown was awarded by video referee Steve Presley, but it was tough on Salford.
Hull?s Paul Cooke and Garreth Carvell were on Friday among the six players called up for the Great Britain train-on squad for the end-of-season Gillette Tri-Nations, alongside Salford pair David Hodgson and captain Malcolm Alker.
The Hull duo had more to smile about, with scrum-half Horne becoming the first player to score in 10 successive engage Super League matches.
The Reds were missing Andrew Dunemann and Simon Finnigan, both injured in last week?s win over Bradford, but John Wilshere returned after a broken bone in his shoulder.
It was Wilshere?s lightning burst which fired Salford ahead after only 16 seconds.
Luke Robinson collected Cooke?s kick-off and fed Wilshere, who rounded Richard Whiting before Aaron Moule finished off the 90metre move to give the Reds a flying start.
Hull were still recovering from the early setback when Danny Lima?s neat off-load allowed Robinson to be the provider again for Hodgson to dart over, with Stephen Myler?s second conversion opening up a 12-0 lead after only four minutes.
Cooke?s needless swing at Robinson allowed Myler to slot over a penalty before Chris Chester?s use of the elbow on Sean Rutgerson under the posts allowed the ex-Widnes half-back to open up a 16-0 advantage.
But Hull were in no mood to surrender their winning run without a fight, and the danger signs for Salford were there when Nathan Blacklock lost the ball over the line.
Hull finally managed the try that was threatening when substitute Graeme Horne waltzed through sloppy defence, with Cooke?s conversion cutting the gap to 16-6 at the interval.
Domic was a tower of strength in the centre for Hull, stopping a certain try with a tackle on Hodgson, but then he could not ground the ball under pressure from Junior Langi over the Reds line.
Salford?s Luke Adamson also failed to touch down from Robinson?s kick just before the break. Hull clawed back to 16-12 early in the second half, Motu Tony catching Salford napping from dummy-half - with Presley awarding the try despite desperate defence by Chris Charles, Alker and Hodgson.
Salford grabbed a third touchdown in the 51st minute with Andy Coley?s crossfield surge sending Wilshere over in the corner.
Then Horne shot over from Richard Swain?s pass to cut the gap to 20-18 midway through the second half, before Raynor?s dramatic winner.
Salford: Hodgson, Langi, Littler, Moule, Wilshere, Myler, Robinson, Lima, Alker, Rutgerson, Coley, Sibbit, Charles.
Replacements: Williams, Highton, Haggerty, Adamson.
Hull: Tony, Blacklock, Whiting, Domic, Raynor, Cooke, R. Horne, Dowes, Swain, Carvell, Radford, McMenemy, Chester.
Replacements: Briscoe, G. Horne, Wheeldon, King.
Referee: S Ganson (St Helens)