Struggling Chesterfield slumped to a seventh defeat of the season as the pressure intensified on manager John Sheridan.
The hosts had taken the lead through towering forward Tom Denton, but goals in each half from Tyrone Barnett and Marcus Barnes handed Eastleigh the three points and kept the home side in the bottom four.
Chesterfield started brightly, with Curaçao international Gevaro Nepomuceno a constant menace.
His trickery down the left flank saw him whip a cross in Denton in the third minute, but the striker headed the ball into the ground and it bounced over the bar.
Sheridan’s men took a deserved lead in the 16th minute when Nepomuceno and Denton linked up again with the latter heading beyond Eastleigh goalkeeper Max Stryjek at the back post.
Chesterfield continued to press and should have doubled their lead when Denton’s scuffed shot fell to captain Will Evans, with the former Eastleigh defender firing just wide.
Nepomuceno also went close before Eastleigh levelled through Barnett.
The striker met Jack Payne’s long throw and flicked the ball past Jalal.
The home side could have regained the lead two minutes into the second half when Scott Boden beat the offside trap, but he took one touch too many and Rob Atkinson cleared the ball out of play.
And Chesterfield were made to pay when Eastleigh took the lead in the 55th minute through Barnes.
The on-loan Southampton striker picked a loose ball up in the area and blasted it into the top corner.
Referee Simon Mather should have sent off Rob Atkinson as the clock ticked down when he brought down Anthony Spyrou on the edge of the box, but was only shown a yellow.
The resulting free kick saw Liam Mandeville set up Mike Fondop, but the substitute’s effort hit the side netting as Eastleigh held on for points.
Chesterfield: Jalal, Yarney, Evans, Wedgbury (Fondop, 71), Nepomuceno, Hollis, Rowley (McGlashlan, 68), Mandeville, Weston, Boden (Spyrou, 62), Denton. Unused subs: Coddington and Wakefield.
Eastleigh: Stryjek, Partington, Atkinson, Boyce, Green, Barnes (Williamson, 75), Miley, Smart, (Seaman, 86), Payne, Hollands, Barnett (Rendell, 81). Unused subs: Flitney and Bearwish.
Referee: Simon Mather.
Attendance: 3,632 (away attendance 65)