Guiseley remain in relegation trouble after a 2-0 defeat at Brackley means they have now won just one of their last 17 fixtures and suffered four straight away defeats.
Brackley came into the game on a fine run of form having won their last seven home league matches, while the Lions were still looking over their shoulder at the National North relegation zone.
The hosts started the brighter side with Lee Ndlovu breaking forward and only being denied by a fine block by Josh Langley.
They then came even closer to getting a goal when James Armson headed over from six yards out.
Guiseley had two good chances of their own to take the lead, a cross by Kaine Felix was headed on by Will Hatfield – who did well under pressure to make contact but it drifted just wide.
This was followed by a chance for Michael Fowler who did well to find space in the area but his shot lacked power and was well saved.
Brackley took the lead when Shane Byrne hit a well-placed finish into the left-hand bottom corner just before the break.
A bad end to a half was followed by a terrible start to the second half as the hosts doubled their lead moments after the restart, as Connor Hall netted with a free header.
Guiseley really should have conceded more but a combination of some mis-placed shots and poor touches in attacking positions meant it remained 2-0.
The Lions now find themselves just four points clear of the relegation places.
After the match, Guiseley joint-manager Marcus Bignot said: “We left ourselves a mountain to climb in the way we conceded both goals and the timing of them as well.
“We have competed against two sides fighting for the play-offs and despite the losses we can take something from them games.”
Guiseley next face Ossett United in the West Riding County Cup final at Ingfield Stadium tomorrow followed by a crucial league match against Ashton United at Nethermoor next Saturday.
Elsewhere in National North, in-form ex-York City strikers Joe Ironside and Ashley Chambers, meanwhile, ensured Park Avenue went down 3-0 at play-off chasing rivals Kidderminster.
Ironside made the scoresheet for a third consecutive match by bagging a brace either side of Chambers’ header, which represented his sixth goal in the Harriers’ last three home matches. Defeat left Bradford with just two points taken from a possible 12 during their last four winless contests.
Macaulay Langstaff grabbed the only goal in York City’s 1-0 home win against Southport.