John Sheridan tore into his Chesterfield players after they lost for the seventh time this season.
Tom Denton gave the hosts the lead, but goals either side of half-time from Tyrone Barnett and Marcus Barnes handed Eastleigh the three points.
This latest defeat sees the struggling Spireites remain in the bottom four.
Frustrated manager Sheridan revealed: “I keep trying to get answers out of them about what goes through their mind when they go a goal up when we need to control the game.
“I cannot do it for them once they are out on the pitch and I am seeing the same things week in, week out.”
Chesterfield had taken a 16th-minute lead when Gevaro Nepomuceno sent a ball to the back post for 6’7” forward Denton to head beyond Eastleigh goalkeeper Max Stryjek.
But Eastleigh equalised on the stroke of half-time when Jack Payne’s long throw was met by Barnett, who flicked the ball past goalkeeper Shwan Jalal.
The visitors added another in the 55th minute through Barnes when the on-loan Southampton striker picked a loose ball in the area and sent the ball into the top corner.
Sheridan added: “Their first goal; it was a bad time to concede and we had even showed them during the week Eastleigh’s long throws and we worked on it.
“There’s nobody challenging their player when the ball comes in from the throw - it’s just ridiculous.
“Nobody is reacting again when they score their second goal.
“They must get a grip of each other because they do not say a word to each other on the pitch.
“There’s a bit of talking during the game, but it should be going on for 90 minutes.
“I am frightened watching us play because of the way we leak goals, but we are where we are and I’m going to keep working my socks off to try and turn it around.”
Sheridan also defended substituting Scott Boden, a decision which did not go down well with the home fans.
He said: “Boden was probably offside around eight times.
“With their first goal, he switches off and is talking to the linesman.
“They take a quick free kick and the ball comes to where he should be reacting, so it goes out for a throw in which leads to their goal.”