Preston boss Phil Brown called for renewed commitment from his players after their second successive defeat at Walsall.
North End had enjoyed a run of seven consecutive victories before losing to then bottom club Leyton Orient in their last outing, and things failed to improve at the Banks's Stadium.
Alex Nicholls' 11th-minute strike proved enough to secure a first league triumph in eight for the Saddlers, who also played the final 20 minutes with 10 men.
"It wasn't the result or performance I wanted," Brown said. "From start to finish it was a bad day at the office, including the (ankle) injury to Neil Mellor.
"The last two or three times we haven't put the shirt on with any kind of pride, passion, commitment or thought process, and it's my responsibility to come up with the answers. I didn't see any kind of commitment by the players towards the badge or the shirt."
Asked about his change of formation in the second half, Brown replied: "I don't think it's about systems or formations, it's about players, and we had too many who lost their individual battles. I don't think we were comfortable at any stage in the game or played with enough quality that is required to cause Walsall problems."