Celtic manager Neil Lennon has suggested that tiredness was to blame for his side's 1-1 draw with St Johnstone on Sunday.
The Hoops failed to emulate their Champions League heroics against Barcelona in midweek as they missed the chance to go top of the Scottish Premier League table at Parkhead.
"We have played considerably more games than any other team in the league, nine or 10 more and we are only into November," said Lennon.
"There was a flatness and lethargy but that's the amount of games catching up."
Celtic are back in SPL action on Saturday when they travel to third-placed Aberdeen.
