Neal Ardley admitted he felt a "bit let down" after Notts County were beaten 3-2 by Maidenhead at Meadow Lane.
The Magpies had taken an early lead through an instinctive finish from Jimmy Knowles after three minutes only for the lead to be wiped out by a thunderous strike from Sam Barratt.
But Ruben Rodrigues' first goal for the club put Ardley's side back in command only for Barratt to score his second of the game with a header from a set-piece.
And the win was wrapped up for the visitors when Danilo Orsi ran clean through to clip over the advancing Sam Slocombe.
Notts were missing several first-team players amid an outbreak of positive tests but Ardley said that was no excuse for the defeat.
"I'm not happy," he said.
"With everything that's gone on with the rigmarole of what happened with the Covid tests, and the game being on, you feel a bit let down.
"That team was good enough to win a game of football. We scored two goals at home and you expect to win.
"We do our homework on the opposition and they're a big strong team at set-pieces.
"We made sure the players knew their jobs, but as a manager there is nothing more frustrating when a player doesn't do his job.
"I'll get the criticism for it but it's happened twice and it's left us chasing our tails.
"But we should have been out of sight in the first half."
