Leicester boss Richard Cockerill slammed his team's performance after the Aviva Premiership leaders were held 41-41 by Gloucester in a remarkable contest at Welford Road.
The Tigers led by 14 points with 18 minutes left, but they failed to put third-placed Gloucester away. And the visitors claimed the highest-scoring draw in Premiership history when fly-half Freddie Burns converted an interception try by centre Eliota Fuimaono-Sapolu with the game's final kick.
"There were that many mistakes and loose passes, I don't know whether some of the players thought it was a testimonial match," he said. "We have got to be better than that. We set our standards high, and that wasn't good enough."
He added: "Next week will be an uncomfortable week for some. At 14 points clear, we made mistakes and let them run through us, and we ended up conceding five tries."
Fuimaono-Sapolu's second try, and Burns' conversion, also ensured it was the most points Leicester have ever conceded on home soil in a league game.
Tigers looked as though they would bounce back from their painful European exit against Leinster last Saturday with victory, especially after juggernaut wing Alesana Tuilagi scored three tries in 14 minutes to ruthlessly overturn an interval deficit. But Gloucester drew level at 34-34 before Leicester centre Billy Twelvetrees claimed what appeared to be a winning score midway through the final quarter.
Gloucester though, had other ideas, and the brilliant Samoa international Fuimaono-Sapolu claimed his second try when he intercepted Jeremy Staunton's pass 60 metres out, and Burns goaled.
Gloucester led 17-13 at the break following touchdowns from full-back Olly Morgan and Fuimaono-Sapolu, but Tuilagi then cut loose as he took his Premiership try tally this season to 10.
England fly-half Toby Flood converted Tuilagi's treble and also added the extras to an early Scott Hamilton score and Twelvetrees' touchdown, while two penalties meant he finished with 16 points. Gloucester though, confirmed their status as probable play-off qualifiers, with flanker Andy Hazell and substitute centre Tim Molenaar adding second-half tries before Fuimaono-Sapolu and Burns provided the finishing touches.
Cockerill added: "Gloucester proved they are a good side. If we end up meeting them again in the play-offs, it will be a tough game."