Pat Rayment was not happy – despite a six-goal haul on the road putting Spalding United back into the play-off places.
The Tulips boss blasted the second-half performance at rock-bottom Brigg Town on Tuesday night.
Rayment cancelled plans for Thursday night off by calling in the players for a training session.
The midweek 6-1 win sent Spalding into fifth spot in the Evo-Stik League First Division South ahead of Saturday’s home game against Market Drayton Town.
Rayment said: “At half-time on Tuesday I told the players that I didn’t want the second half to turn into a practice game and they let me down.
“It was an opportunity to get going again, hit some form and give ourselves a platform.
“I know I’m hard to please but we gave away a sloppy goal at the end and we should have scored double figures.
“If we had done things properly then we would have put our goal-difference up by a few more.
“The lads have ability but we have to push them all the way when they get sloppy.
“The last 45 minutes were not good enough and that’s very frustrating.
“The players have got to give us more urgency.
“They need to step up to the plate because we’ve got a big game on Saturday followed by away matches at Gresley and Stafford Rangers.
“Even during our 15-match unbeaten league run we could see the performance levels were deteriorating.
“We need to get back to doing the right things.”
Left-back Adam Jackson completes a suspension this weekend as former Holbeach United striker Matty Nolan starts a three-match ban.
Central defender Nathan Stainfield should return from resting a knee injury.