United found themselves behind to the first attack of the match after five minutes, when Shaun Findlay was allowed too much space to cross into the area for Mark Cave to place across the returning Russ Tanner.
The Magpies doubled their lead on the half hour as Michael Wood and Oliver Gill combined in the centre of the park, with Gill placing a left footed strike past the outstretched dive of Tanner. United struggled to find any rhythm to their play, with any attacking play muted by the visiting defence before it reached an area of danger
In added time at the end of the first half, Tanner had to make a strong save at his near post to deny Matt Hoyte from increasing the scoreline.
Paul Rogers was introduced to the action at half time in a bid for a bit more attacking physical presence, but the game was effectively over before he could even touch the ball as Loxwood scored inside the first minute.
A long ball was miscontrolled by Andy Corrigan and pounced upon by Findlay, who crossed the ball to the back post for Wood, who rifled a volley past the helpless Tanner.
United lost Ben Farrant to a dead leg ten minutes into the half and he was replaced by Adam Davidson, who resigned for a second spell at The Oval on Friday morning.
In the 66th minute, United had their first and only shot on target of the match as a quick free kick saw Lucas Mann put through on goal, but Sam Smith was equal to the strikers drive.
Further chances fell to Loxwood, with Tom Familton and Gill both seeing efforts saved by Tanner as United will look to put the defeat behind them and forget a bad day at the office.