"The pressure was on tonight," McGuinness explained just minutes after the final whistle had blown.
"They came through the match and I suppose in relation to our (Donegal) own journey there are a couple of similarities.
"A lot of people had Celtic written off at the start of the season, saying that they wouldn't be in the group stages let alone the last 16.," he said.
"It's been a great journey for them. I see how hard they work in training.
"They are a very honest group of lads and have delivered for the club.
"Who knows what the draw will bring and that's part of the excitement," he said.