Wycombe manager Gary Waddock bemoaned his side's lack of consistency after watching them succumb 4-1 to 10-man Scunthorpe.
A sixth successive away defeat plunged Wanderers to the foot of the League One table after Scunthorpe struck twice in each half.
Paul Reid opened the scoring, Andy Barcham scored twice and Jon Parkin made it four before Matt McClure headed an 86th-minute consolation goal for Wycombe.
"As well as we played last week to beat Hartlepool 5-0, we were the complete opposite. We were very, very poor," said Waddock.
"All credit to Scunthorpe for the way they played, but we just did not turn up.
"At the moment we just don't know what we are going to get from the team - and I don't know why."