Nobody would have predicted such a romp before the game but that was exactly what happened.
Widnes lost Stef Marsh and Chris Dean to injuries and they never recovered.
Shaul was the star of the show with an impressive display at full-back. He was well backed up by 17-year-old Lancaster.
It was his try that got Hull ticking over, after Paddy Flynn had initially broke the deadlock for the home side.
Mickey Paea was next to cross as Hull looked to take the advantage after Widnes were making up errors in both attack and defence. Paea charged onto a short ball from Richard Horne to scatter the Vikings defence for his easy try.
Jordan Rankin converted and then added a penalty just before the break to make it 14-6.
Talisman Kevin Brown could not drag his side into any sort of position of power and the Vikings slipped further behind after lapses in concentration.
Lancaster finished off a brilliant break from Jordan Thompson and it was all too easy for Lee Radford’s side.
Things did not get any better for Widnes and Fetuli Talanoa sent in Shaul for another score which effectively ended the game as a contest.
Aaron Heremaia was then brought on to complete the demolition job from the ruck and he created a try for Horne, who scampered over for another simple try.
Lancaster completed his hat-trick on 74 minutes as Widnes were running on empty. Horne raced in for a sweeping Hull score and then Rankin flew in for a solo effort to finish the night with a 24-point haul with a try and 10 goals.
There was still time however for Shaul to run in another to leave Widnes floored.
Widnes: Hanbury, Owens, Dean, Marsh, Flynn, Brown, Gilmore, Johnson, Clarke, Kavanagh, Tickle, Galea, Leuluai. Substitutes: White, Allen, Joseph, Cahill.
Hull: Shaul, Talanoa, Crooks, Yeaman, Lancaster, Horne, Rankin, Paea, Houghton, Watts, Ellis, Tuson, Westerman. Substitutes: Heremaia, Paleaaesina, Sa, Thompson.
Referee: M Thomason (RFL).