The former Dortmund star did his best Peter Schmeicel impression and charged forward in the closing moments of the tie in the hope of snatching an unlikely winner.
To his credit, Gers' German stopper displayed the predatory instincts of a top-class striker and almost grabbed the headlines with a sensational last gasp header.
His point blank effort was palmed away by his opposite number just seconds before the whistle and for an instant Stefan thought he had bagged the all important goal that would have sent his side through to the next round.
He told rangers.co.uk: "Obviously we were all disappointed to go out. We had so many chances near the end to get the goal we needed but it just didn't happen."I was just thinking about putting the ball in the back of the net and it almost happened.
"I remember I had a good connection. It was a great cross from Mikel Arteta and I got up early at a good height and headed it quite well towards goal.
"It should have gone into one of the corners but unfortunately their keeper made an unbelievable save.
"When I was a youth player I played a couple of games as a striker but that was so long ago and I much prefer staying at the other end of the pitch.
"We did everything we could to turn the game round and I think we were really unlucky but I don't think I'll be playing up front against Celtic!
"I feel sorry for the supporters we didn't manage to progress in Europe but hopefully we can give them some joy in the SPL."
Klos will be back between the sticks at Parkhead this weekend and maintains earning an Old Firm victory, on the home patch of their rivals, will help the club recover from the shock UEFA Cup exit.
The German continued: "We were a bit tired when we came into training this morning but we have plenty of time to recover and we'll all be fully fit for Sunday's game.
"We all look forward to playing Old Firm games and it will be a great atmosphere.
"We managed to beat them last season in the CIS and Scottish Cup so we know we are capable of getting a result against them. "We have that winning mentality now and hopefully that can continue on Sunday."