Sutton United manager John Rains has told his players they have a lot of hard work ahead of them to meet his high standards.
Despite a win and a draw in their last two games, Rains believes Sutton are still not playing to their full potential.
He said: "They are all getting better but we seem to be suffering from slight lapses of concentration.
"Things are getting better but I would say we are still playing like an average side."
Sutton eased through to the last 16 of the Ryman League Cup on Tuesday night by recording a 3-1 win at Thame United with goals from Matt Gray, Michael Mison and Rob Haworth.
United's boss added: "We played quite well. The fog was a factor. Everyone did what they had to and were in the last 16 with a 3-1 win.
"There are areas we need to improve on. All of them. We have to create more chances and defensively we have to get better.
"I have learned that we need to improve when teams have a good 15 to 20 minute spell in games. That's what has cost us."
With the draw not being made for two weeks, Rains will have to wait to find out who his side will face in the next round.
Sutton entertain Braintree Town at Gander Green Lane tomorrow and will be looking to build on their recent results.
Rains said: "They have done well this season. Braintree have taken many people by surprise.
"The showed us what they could do when we faced them on the opening day of the season."
Danny Brooker (hamstring) is Sutton's only absentee.
December 14, 2001 15:30
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules hereComments are closed on this article