In front of a crowd of 1,010, the Ammies were looking to add to their own unbeaten run of five matches, but fell behind after just 4 minutes when Aaron Williams got on the end of a cross to head home.
And it was 2-0 after 17 minutes when Alex Gudger scored from a Shane Byrne cross.
It was 2-0 at the break and Glenn Walker and Jimmy Armson both came close to increasing the Saints` lead in the second period.
There was a late scare when Salford grabbed one back in stoppage time through Jake Beesley from a free-kick and a goalmouth scramble.
But the Northamptonshire side held firm and hold a healthy twelve point advantage over the eighth-placed side and nine behind Salford.
Second-placed Harrogate Town made it five straight wins at The CNG Stadium and moved to five points behind the leaders with a 2-0 win over second-bottom AFC Telford United.
Joe Leesley opened the scoring with his 18th goal of the season, curling a sublime effort into the top corner after 33 minutes.
The hosts added a second 6 minutes after the break through Simon Ainge`s header from a Jack Emmett cross.
The Bucks did manage to pull one back as Jordan Murphy netted in the 90th minute to set up a grandstand finish, but Harrogate were able to see out the game.
Spennymoor Town are fourth, four points behind Brackley, after a 1-0 Brewery Field win over Tamworth.
There was little goalmouth action until the deadlock was broken in the 25th minute when Mark Anderson set up Glen Taylor for fire home left-footed.
Tamworth showed plenty of effort, but failed to seriously test home keeper Jordan Porter and Moors held on to leap-frog York City in the table.
That was due to the Minstermen suffering their first defeat since Christmas following a 2-0 defeat at Edgeley Park against Stockport County, who are now back in the top seven race.
In front of a crowd of 4,407, the hosts seized the initiative with two goals in 7 minutes through Darren Stephenson after 24 minutes and Matty Warburton on 31 minutes.
The Minstermen improved after the break but couldn`t reduce the arrears and slipped to a first defeat in seven games.
Kidderminster Harriers pick up a comfortable 3-0 win over Southport at Aggborough.
Goals in the 15th minute from Emmanuel Sonupé, 5 minutes later from Fraser Horsfall and then on 26 minutes from top scorer Joe Ironside did the damage in a devastating spell for the hosts.
The home side saw the game out with little trouble in the second half.
Boston United’s unbeaten run continued, and Craig Elliott’s side made it eight games without defeat as they beat seventh-placed Blyth Spartans 2-1 at the Jakemans Stadium.
After a goalless opening 45 minutes, Ashley Hemmings converted his 10th penalty of the campaign to make it 1-0 after 62 minutes.
Dan Maguire responded for Spartans in the 77th minute.
But sub Kabongo Tshimanga’s 13th goal of the season – and 9th off the bench – eventually won it for the home side on 84 minutes.
The result moved the Pilgrims into eleventh and to within five points of their opponents.
Bradford Park Avenue are three points behind the play-off places after sharing a goalless draw with fifth-bottom Nuneaton Town at the LDJ Solicitors Stadium.
Boro were unable to make the most of their opportunities, especially when Avenue`s Danny Boshell was given his marching orders for a second yellow card offence with 17 minutes remaining.
At the other end of the table, there was a crucial win for Darlington as they moved to within a point and a place of Leamington in sixteenth after edging a five-goal thriller at The Phillips 66 Community Stadium.
The Quakers were handed a boost with a 9th minute penalty award which Stephen Thompson gratefully accepted to put his side in front.
However, just 8 minutes later, the Brakes were also awarded a spot-kick for a high boot challenge by Gary Brown and Callum Gittings equalised.
But the turning point came with 5 minutes of the first half remaining when Leamington had Joe Clarke dismissed for a second bookable offence.
But Jack Edwards put the ten-men in front on the hour-mark, only for Thompson to equalise 14 minutes later.
And then as stoppage time ticked in, Thompson completed his hat-trick with a close-range finish and win it for Tommy Wright`s side.
Another early `six-pointer` near the bottom end of the table saw Gainsborough Trinity seal a crucial 2-1 win against Alfreton Town at the Northolme.
Nathan Jarman gave the home side the boost of a 31st minute lead. David Shiels pulled the Reds back on level terms on the hour-mark.
But the hosts won it through Craig King with 11 minutes remaining.
The win lifts Trinity to third-bottom, two points behind the safety-mark and five of the Reds, who are fourteenth.
Curzon Ashton are the side just above Gainsborough now after they lost 2-0 at neighbouring FC United of Manchester.
In front of a crowd of 2,140, The Nash were reduced to ten-men after 35 minutes when they had Joe Guest sent-off to a poor challenge on Steve Irwin.
The visitors held out until 6 minutes after the break when Irwin exacted revenge by giving the home side the lead.
But just 4 minutes later, the on-field numbers were evened-up when FC United`s Kieran Glynn was dismissed for a second bookable offence.
But Connor McCarthy popped up with a second for the hosts in the 72nd minute to seal victory and twelfth spot.
Chorley missed the opportunity to move into eighth place when they were surprisingly held to a 2-2 draw at Victory Park by rock-bottom North Ferriby United.
Brett Agnew gave Ferriby the lead against the run of play in the 19th minute, only for Chorley to hit back immediately through Jason Walker.
Josh O’Keefe gave the home side the first on 56 minutes, but sub Jordan Harrison earned the visitors a share of the spoils with a 76th minute leveller.
Although they did have to defend the final 9 minutes with ten-men after new signing Paul Robson was sent-off on his debut after bringing down sub Khuis Metz as the Burnley loanee was clean through.