Hull opened the scoring with their first real attack after nine minutes, when Jake Connor’s smart flick pass sent Danny Washbrook scampering over, with Marc Sneyd converting.
Hull doubled the lead to 12-0 when an Albert Kelly cross-kick was fielded by the returning Bureta Faraimo, who dummied before spinning out of a tackle and crossing for a six-pointer.
The Vikings came back strongly and, after a couple of penalties gave them field position, quick hands got Sam Wilde in at the corner, with Tom Gilmore kicking superbly to make it 12-6 on 20 minutes.
The remainder of the first half was nip-and-tuck but Gilmore pulled two more points back with a penalty on the stroke of half-time.
Widnes co-captain Chris Houston went close following the restart but was stopped just short and became the latest Vikings injury victim in the process.
Betts’ men continued to press and Tom Olbison sneaked over from dummy half, with Gilmore’s conversion giving his side a 14-12 lead.
It would not last long as Masi Matongo cruised through a huge hole to score under the posts and Josh Griffin soon tore through the Widnes defence to score wide out to make it 22-14.
In the 59th minute, Hull went in again when a Sneyd kick was latched onto by Fetuli Talanoa in the left corner.
Sneyd missed the conversion but was on target with a drop goal with 14 minutes remaining to give his side a 27-14 advantage.
The Vikings refused to give up the ghost and Olbison hit a gap to cross behind the posts for his second converted try.
Widnes kept the ball alive desperately and a loose pass from Aaron Heremaia was latched onto by Griffin, who raced in from halfway. Sneyd added the extras and was on target again when Jamie Shaul added a try at the death to confirm the win.
Widnes: Hanbury, Runciman, Whitley, Dean, Ince, Gilmore, Mellor, Burke, Heremaia, T. Chapelhow, Wilde, Olbison, Houston. Substitutes: Leuluai, Farnworth, Johnstone, J. Chapelhow.
Hull: Shaul, Faraimo, Connor, Tuimavave, Talanoa, Kelly, Sneyd, Taylor, Houghton, Paea, Griffin, Washbrook, Bowden. Replacements: Downs, Green, Litten, Matongo.
Referee: Chris Kendall (RFL)