Former Scotland goalkeeper Craig Gordon made his Celtic debut in a 1-1 friendly draw with Dynamo Dresden on Saturday.
Gordon, signed as a free agent earlier this month, played the first half of a fixture sandwiched between the two legs of Celtic's UEFA Champions League third qualifying round tie with Icelandic side KR.
Ronny Deila's men ran out 1-0 winners in the first leg against KR on Tuesday, but were unable to keep a clean sheet on this occasion after moving ahead through Kris Commons' eighth-minute strike.
Commons drilled home from 12 yards after being set up by Teemu Pukki's lay-off.
However, last season's top goalscorer in the Scottish Premiership was forced off before the interval and Deila then made 10 further changes at half-time.
Dresden, relegated from the second tier of German football in May, subsequently found an equaliser as the pace of play dropped in baking-hot conditions.
An effort from Marvin Stefaniak was cleared off the line in the 68th minute, but Sylvano Comvalius picked up the loose ball and finished calmly.
Celtic were unable to find a winner thereafter and will now turn their attention to a home tie against KR on Tuesday.comments