In an absorbing game, in which both defences ruled, it was a try two minutes from time by home full back James Bird which finally clinched the win.
His conversion attempt from wide on the right sailed trough the posts to deny what would have been a deserved losing bonus point.
For the frist time this season we failed to score a try although many West supporters felt we might have been awarded a penalty try early on.
That incident came on the quarter hour. Home winger Peter Moralee deliberately knocking on as Zac Southern was looking to make the most of a two man overlap just ten meters from the home line.
Moralee was sent to the sin-bin for stopping the move, but referee Phil Stokes decided not to go between the posts for a penalty try.
We attacked from the resulting penalty forcing three successive scrums close to the home line. However, when Ryan Painter did force his way over he was judged to have knocked on and Alnwick finally cleared their lines.
The home side were leading 3-0 thanks to a tenth minute penalty from Bird as Alnwick started the better. We grew into the game and deservedly drew level on the half hour after Sam Miller burst through the defence to take the play into the home 22. Gavin Painter making the most of a penalty after Alnwick were judged to have handled in a ruck.
He was narrowly wide with another effort as most of the play was in the home half, but it was Bird who made the most of his own opportunity ten meters into the West half to give his side a 6-3 half time lead.
Our response from the restart was immediate with Alnwick penalised in their own 22 and Painter opting to level the scores
However, the Northumbrians responded by forcing the first try of the game. A penalty was kicked to the corner and West were penalised for using hands in the ruck with the home side opting for the scrummage which had been serving them well all afternoon.
They drove for the line with flanker James Hamilton touching down. Bird's kick was wide and with Aaron Myers leading from the front we set about trying to overcome the five point lead.
Unfortunately, replacement Jay Corbett was unfortunate to knock on as he barreled towards the line.
Then the visiting forwards forced a series of penalties in the home 22 with both Miller and Aaron Myers going close as the visitor's opted for scrums.
However, coach Dixon intervened to instruct his side to go for the posts as Alnwick were judged to be offside, and Painter's kick brought the lead back to just two points.
Alnwick attacked from the restart and seized the initiative when a clearance kick from Ryan Painter was chased down by Rob Thorn and Lee Maddison but both were judged to have been in front of the kicker.
We were forced to defend in their own 22. Unfortunately, we ran out of numbers as the home backs spun the ball our right with Bird coming into the line and going over close to the corner to set himself up for that last kick.
Alnwick: James Bird, Peter Moralee, Sean Hutchinson, Frank Hutchinson, Rory Mallaburn, James Warcup, Hugh Todd, Duncan Smith, Hamish Burn, Colin Phillips, Richard Ellis, Ollie Sutheran, Gordon Smith, James Hamilton, Ben Gothorpe.
Reps (all used): Peter Brown , Simon Ord, Ben Courty.
Tries Hamilton Bird.
Pens Bird (2)
West: Zac Southern, Rob Thorn, Eldon Myers, Peter Youll, Will Hilditch, Gavin Painter, Ryan Painter, Tim Blades, Andrew Rollins, Ross Wood, Joe Rafferty, Dan Boatman (captain), Aaron Myers, Lee Maddison, Sam Miller.
Reps (all used): Greg Edwards, Alex Barker, Jay Corbett.
Pens: G Painter (3)
Referee: Phil Stokes (Liverpool)