Mark Robson admitted the arrival of Edgar Davids did not have the desired effect on Barnet at the weekend.
The Bees surprised the football world - and Robson - when they named Dutch legend Davids as joint-head coach on Thursday. But the former Juventus and AC Milan midfielder's first match in the dug-out ended in a thumping 4-1 home defeat by Plymouth, leaving Barnet seven points from safety at the foot of League Two.
"I thought the second half was the worst performance I've seen so far," said Robson.
On suddenly becoming a joint-manager, Robson added: "It has only just happened so we will have to see how it pans out and how it develops.
"Coming in the other day there were some big changes so it was a little bit strange but we'll move on from it and try to make it as positive as we can."