The winger believes it can be attributed to rustiness and feels sure another hard spell of training, coupled with Friday’s final warm-up game against Davie Moyes’ Real Sociedad, will ensure Celtic are in the right shape for the first leg with the Icelandic champions on 15 July.
“I’m confident we will be ready in time,” said Forrest. “If you look at the first friendly we played, we didn’t concede a goal. Obviously, we conceded a few in this one but they were a good team.
“The minutes all the boys played will be good for everyone and we will keep working hard ahead of the qualifiers.
“I think the coaches have been to watch a few of their games so they will get us ready. And we know that they played Motherwell last season and got a good result.
“Obviously, it will be a hard game and we need to all make sure that we are fit and ready for it.
“I think a lot of the boys have just come back to training. There have been players arriving at all different times during the week.
“It was good for everyone to get a run-out and get back to a match situation. I thought we played some good stuff at times, but obviously there are a lot of things we need to work on. It’s always hard defensively in these games when you make that many subs and change things around. But we need to make sure we don’t concede the same amount again in the next friendly.”
Leigh Griffiths, with a penalty, Gary Mackay-Steven and Virgil van Dijk were on target for Celtic but they were comfortably defeated by Dukla who in Marek Hanousek had the outstanding player of the game.
The 23-year-old midfielder scored a hat-trick and created another goal in all-round terrific performance which cannot have gone unnoticed. It may have been a pre-season friendly but Hanousek looks as though he has the quality to play at a higher level.
Celtic were simply off the pace although the Czechs are a couple of weeks ahead in terms of pre-season preparation.
Forrest, of course, will never forget the feeling of joy when he fired Celtic into the Champions League group phase two seasons ago in the most dramatic fashion.
Two goals down from the first leg against Shakhter Karagandy, goals by Kris Commons and Georgios Samaras hauled Celtic level in the tie, then Forrest hit the clinching goal in injury time.
He said: “Getting through to the group stages is class. Celtic should be in the Champions League and that night against Shakhter Karagandy was unbelievable. It is something I will never forget. All the boys want that feeling again. We all just hope that we can go and do it over the next few games in the qualifiers.
“We didn’t make it last year but that’s football. We have a good squad this year and all the boys have come back looking sharp. The big aim right at the start of the season is to get that Champions League place and that’s what we are all working to try and do.
“It’s the most important thing and it comes right at the start of the season. In that way, it’s probably good that most of the boys haven’t had much time off. Everyone is near enough fit getting back into things. It will just take a couple of games to get right back there.”
Forrest feels he is a stronger player now after a tough time with injuries and he is looking to make a major impact in the forthcoming campaign.
He said: “The last six months of last season were good for me. I’m glad the break wasn’t too long over the summer and I could keep ticking over. Now I just want to kick on again in the new season.
“I’ve had problems in terms of injuries, but that happens. A lot of players go through it. Some are lucky enough to avoid it in their careers.
“But it is about how you deal with it. Hopefully, I have come back stronger. I feel that’s what I did in the last six months and now I just want to continue like that.”