Forrest was on target in the first leg in the Czech Republic as Celtic finally secured a first win under Ange Postecoglou four games into his reign.

"Even the presence of Joe Hart when he came in for his first session was massive," Forrest said.

"It's great signings from the club and they will definitely help the dressing room. It's really exciting to play with players of that quality and experience.

"Joe Hart's first training session, you could hear him talking the full session, and he's a presence in the dressing room.

"We have not met McCarthy yet but everyone has seen him play and with the experience he has had with Ireland as well, he will be a great addition to the squad.

"There's a lot of quality at the club and a lot of young boys have done well in training but those two signings, you just feel a difference straight away.

"It's not putting any pressure on them, they have obviously played under loads of pressure in their career before, but it's a massive boost. It's really good for the young lads and the senior lads as well."

There remains room for improvement in all areas of the pitch for Celtic but Forrest feels the much-needed win will give them a platform ahead of Sunday's cinch Premiership clash with Dundee at Parkhead.

"It's good to get a win, score some goals and feel good about ourselves again and obviously it gives us a good lead going into next week and hopefully we can build on that," he said.

"It was just important we stopped the mini rut and got that first win. Hopefully we can build on that and performances will gradually get better as well."