Mixu Paatelainen has said that Dundee United were "absolutely rubbish" during their 5-0 loss to Celtic.
The Finn took over from Jackie McNamara earlier this month but has lost his first two matches as manager.
"It doesn't matter what you do on the training ground, if it doesn't happen out there on the pitch," Paatelainen told BBC Sport.
"All that goes in the bin. No wonder we are where we are. It was so disappointing.
"There is plenty to improve on. An unbelievable amount - from defending to attacking. We can't tolerate these kind of standards."
United are currently five points adrift at the foot of the Scottish Premiership table.
