Sir Alex Ferguson has branded Manchester United's 2-2 draw with West Brom as "inexplicable".
After surprisingly choosing to leave Wayne Rooney on the bench, Ferguson saw his side make the perfect start through the striker's replacement Javier Hernandez.
Nani doubled that fourth-minute advantage before the break as United looked set to stroll home.
But after losing Ryan Giggs to a hamstring injury, United collapsed in a six-minute spell after the interval, with Patrice Evra scoring an own goal before Edwin van der Sar's calamitous mistake presented Somen Tchoyi with an open goal.
"It is an inexplicable result and obviously frustrating," said Ferguson.
"I suppose there are two ways of looking at it. If we were in the middle of the league we could say we were still undefeated. For us it is not good enough."