Mauricio Pochettino blamed Tottenham's lunchtime lethargy this season on the Europa League campaign.
Of 10 Premier League matches kicking off at noon, 12:45 or 1:30, Spurs have won two -- against QPR last August and Arsenal in February -- collecting nine points out of a possible 30.
Six of the matches followed Europa League games on Thursday nights, and Spurs lost four of those and drew the other two.
Pochettino, whose side play his former club Southampton at 12:45 at St Mary's on Saturday, said: "Maybe this is a coincidence. Or maybe this is because we play Thursday around Europe and have no recovery.
"I don't know. It's difficult to understand why. Maybe it's because we have played Thursday night and spent a lot of energy."
Spurs have fared better in later kick-offs.
Pochettino said: "Maybe three or four hours more of recovery is better. That can affect that."