Boston beat a below-par Chorley to end the Magpies’ unbeaten home record in the Vanarama Conference North.
Goals from Dayle Southwell and Kaine Felix gave the Lincolnshire side all three points and by the time Mark Ross scored a rare goal, Chorley were already defeated.
It was a fixture that Chorley struggled to get going in and the Magpies will now be looking to bounce back in an immediate return against their Lincolnshire opponents this Saturday.
Boss Garry Flitcroft said: “A couple of things went against us – we lost our skipper Andy Teague early on and we had to bring on Adam Mather, who is a left-back, at right-back.
“Then our goalkeeper Danijel Nizic pulled his thigh and I felt the second goal came from there – it was a poor kick from Tom Smyth and they scored.
“It was a big blow losing Andy Teague but I think a couple of lads didn’t play well, and when you have lads missing, you need everybody to step it up.
“We just didn’t put Boston under pressure enough, James Dean looked quite sluggish and when we play well, he needs to play well.
“Some of the lads struggled in the first half .
“But in the second half we went at them a little bit.
“It’s our first home defeat since March.
“I said to a few of the lads it’s a disappointing way to lose it, especially when a few of them weren’t up for it.
“But we will look to bounce back on Tuesday against Barrow in the Lancashire Trophy.
“It’s a game where the lads will be able to prove whether or not they want to be in the first team.”
A hint of the way the day would pan out was when talismanic Teague was replaced with an ankle injury after just 10 minutes.
Adam Mather came on so the defence needing re-organising, with Ross moving into the centre of defence.
Even before then, Boston had thought they had scored but their goal was ruled out for offside by the alert linesman.
In reply, Paul Jarvis’ cross towards the back post was just over the head of Josh Hine.
After the substitution, Kaine Felix turned in the penalty area to fire a shot which on-loan Magpies keeper Danijel Nizic got down to save well, then Chorley had a penalty appeal turned down by referee Tom Neild.
Nizic was called into action again to save a Dayle Southwell shot and moments after, the same man headed over a centre from Scott Garner.
With 10 minutes of the first half remaining, Boston took the lead, a swift counter attack from the visitors saw Southwell comfortably head in Felix’s cross for his 10th goal of the season.
An almost calamitous mistake from Nizic moments after almost brought a second Boston goal as his clearance cannoned off the back of Felix 20 yards out, but the ball bounced just wide of the Chorley goal.
Boston were intent on going further ahead and Garner’s effort shook the crossbar.
The Magpies defence also had to scramble the ball out the danger zone as Liam Marrs and Southwell had chances.
In the second half, Nizic played on with a thigh strain and the visitors doubled their lead when Felix’s shot towards goal took a wicked deflection off Ross.
Zack Mills hit the wall with a free-kick from distance.
But as the visitors sat on the lead, Chorley grabbed a consolation when a corner wasn’t dealt with and the ball fell kindly to Ross, who volleyed in for his second goal of the season.
Chorley: Danijel Nizic, Mark Ross, Paul Jarvis, Andy Teague (Adam Mather 10), Tom Smyth, Jake Cottrell (Chris Almond 60), Josh Hine, Dale Whitham, James Dean, Harry Winter, Jack Dorney (Darren Stephenson 52). Subs not used: Jack Lynch, Adam Roscoe