Pat Baldwin admitted the Exeter City dressing room will be an unhappy one until they sort out their defending from set-pieces.
The Grecians, who travel to Northampton Town this Saturday, are still searching for their first win of the season, having let a 1-0 lead slip at home against York City last weekend.
The goal they conceded came from an 82nd-minute corner as the ball was floated to the back post and headed home by Keith Lowe.
It was a game City should have won on the balance of play but, having watched his side throw away two vital points, Baldwin said the players were sad and disappointed by what had happened.
"It is not a happy dressing room at all, far from it," said the City vice-captain, who added that the players must take responsibility for the result.
"Tis (Paul Tisdale) can do no more. We work on set-pieces at the training ground and it is down to us players to get better on the pitch.
"Tis can't get on there and organise for us. He can only set us up like he has been doing in training and it is up to us to get it right on the pitch and for that split second on Saturday we didn't do that.
"It is a good delivery, but it is a simple game of maths. They had more people at the back post than we did. It is something we need to look into and correct."
Northampton, with their height and strength, are likely to cause problems from corners and free-kicks again this weekend.
However, Baldwin is adamant that every team in the division will look to profit from set-plays against the Grecians if they do not improve.
"This league is all about set-pieces," he said. "They are vital at both ends of the pitch. Most teams in this division are going to be looking at their set-plays especially against us, so we need to get better and we need to improve which I'm sure we will."
Other than the late lapse in concentration on Saturday, City put in an impressive performance against York.
Midfielder Matt Oakley was the star performer as he lined-up alongside Pat Baldwin in a three-man defence.
Baldwin was not surprised the 37-year-old's ability to switch positions with ease.
"Matt is a fantastic player and a very intelligent player as well, he can play anywhere on the pitch," said Baldwin.
"He was good to play alongside and it was an added voice in there.
"I thought for the majority of the game the defence, in open play, was decent. The first half performance was pleasing, we put a lot of work in, but there is not point working that hard when you throw the points away in the second half."
