Nottingham Forest lost their first league game under Colin Calderwood on Tuesday night as Oldham Athletic ran out 2-0 winners at the City Ground.
The manager told the club website: "We were on a good run and it was important that we kept that run going.
"It's a slap in the face - it's something that we knew we would have to accept at some time in the season but it doesn't make it any easier."
