Hayes & Yeading edged closer to relegation after losing to Mansfield, who secure a play-off place.
United are now four points from safety with two games to play, although Telford above them have a game in hand.
Anthony Howell gave Mansfield an early lead finding the bottom corner of the net before Piero Mingoia tapped home from close range to equalise.
But Ross Dyer's volley from 20 yards and Matthew Green's strike from the edge of the box sealed the victory.
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Mansfield Town manager Paul Cox told BBC Radio Nottingham:
"I think performance-wise, we were very, very below par today. It was a difficult game, psychologically, coming into it we looked to get just over the finishing line.
"Sometimes psychologically has an impact on us and today we looked well below what we can do.
"Give credit to this group of players. Throughout the season they've re-invented themselves, they've worked extremely hard and they've deserved the results they've got."