Toprak and his team-mates were embarrassed in the first leg of their last 16 tie against Paris-Saint Germain, losing 4-0 in front of their home fans in Germany.
Leverkusen were humbled 10-2 on aggregate by Barcelona at the same stage of the 2011-12 competition, with a 7-1 defeat in the second leg particularly humiliating.
Sami Hyypia's side have not won in their last six matches, seeing them slip to third in the Bundesliga, and there seems little to play for in Wednesday's second leg in Paris.
Toprak sees it differently though, and is adamant his side will put in a fighting display in hope of restoring their credibility.
"It is hard to understand how we could start a last-16 match in the Champions League in such a spiritless way, not strong in the tackle – that is hard for us to understand," he told UEFA.com.
"But we have to work on it, trying to do things better.
"It's now difficult to travel to Paris having lost 4-0. It was difficult enough before the first leg – and the possibility of making it is very, very small.
"But we want to go to Paris and show we can do better. We have to go out on the pitch in a totally different manner and feeling. We will have a go, but it will be very tough."
Leverkusen winger Sidney Sam, a key figure in the club's terrific early season form but with just one goal since October, admits a "miracle" is needed if his side are to qualify.
"Of course it will be difficult to make it, you need a miracle to make it happen," he said.
"But we still want to perform well and do better than the first match."
