Three debutants were on show, New Zealander Blake Steele on the right wing, flank forward Ruane Fourie from South Africa and local boy Ethan Robertson on the left wing.
All three played with great determination but at the final whistle their efforts were in vain in a game between two well matched sides.
In the first meeting between the two clubs at Greensfield since March 2000 both sides began on a positive note despite the heavy rain.
Vale fell behind to a fourth minute penalty kicked by James Bird, following a high tackle.
Then a well co-ordinated forward drive resulted in a Vale penalty, but Alex Briggs, who produced a confident performance, failed to hit the target in the 11th minute.
The game quickly settled down into a pattern with the respective defences on top.
Vale’s pack looked comfortable with the ever reliable Andy Powers and Ross Pillow in the thick of the action, with great support from locks Adam Foxcroft and Harry Fellows, Alnwick were forced to work hard for their openings.
Alnwick did compress Vale to force a penalty which Bird kicked in the 19th minute.
There was another penalty from the same player six minutes later at the end of a fine attacking period from Vale during which fullback and man of the match Jordan Dorrington was the main instigator.
As the half drew to a close, Vale came more and more into the game and in the 30th minute they were rewarded with a converted try.
Converted centre Jack Ayrton made a slashing break, Will Hunt appeared at his shoulder to touch down between the posts, Briggs adding the conversion.
Vale began the second half very much in contention but urged on by their supporters Alnwick gave them plenty to cheer about and the home side extended their lead with another Bird penalty in the 48th minute and he was on target again 12 minutes later.
Vale by now were beginning to lose momentum and the tide had really turned in the home side’s favour.
Their victory was confirmed when prop Duncan Smith exposed some weak Vale tackling in a daunting run that saw hime cross for an unconverted try.
That was the signal for some extreme Alnwick pressure but brave and resolute Vale tackling prevented them from scoring again.
Vale face a daunting task on Saturday when they host league leaders and promotion chasers Hull.
Vale of Lune: J Dorrington, B Steele, W Hunt, J Ayrton, E Robinson; A Briggs, B Swarbrick; M Bradshaw, A Powers, R Pillow, A Foxcroft, H Fellows, A Crookall, R Fourie, S Wallbank. Reps used: S Tagge, D Rainford, H Finan.