The Minstermen crashed to a 3-0 defeat at Northampton Town last week with an error-ridden display.
Coming just a week after a heartening 2-0 win at home to relegation rivals Tranmere Rovers, Wilcox was fuming with his players.
“It was so frustrating,” said the York manager. “We have been a Jekyll and Hyde side ever since I came to the club and Northampton was one of those lows for us.
“The biggest disappointment was it came on the back of a really big win. We just made too many mistakes and that is why this week in training has been all about getting back to basics.
“We have done a lot of work without the ball, making sure we have a better shape and are better able to cope with defensive situations.
“Clearing our lines is something we need to improve along with doing all the basic things right.”
The win over Tranmere a fortnight ago was only York’s second at Bootham Crescent this season. With four of the bottom six still to visit York, Wilcox recognises that improving the club’s form on home soil could make all the difference.
He said: “We played well in our last home game so the players have to use that and take it into Exeter City as proof we can play well.
“It is a positive and we need to repeat it. We have a lot of big games coming up at home and it is important we take advantage, especially against the sides down there with us.
“Points are what matter at this stage of any season. And if it has to be a bit scrappy then so be it.”