Union Berlin manager Urs Fischer was confident on Monday his struggling side would get "back on track" against Napoli in Tuesday's Champions League clash.

Champions League debutants Union host the Serie A winners in the German capital on Tuesday night on a horror run of eight straight losses -- by far the longest streak since the side's first-ever promotion in 2019.

"We're making another attempt at getting back on track" the Swiss manager said, telling reporters in Berlin his side would approach the clash "with confidence and positive energy."

Union are still chasing their first point in the competition, having suffered injury-time defeats away at Real Madrid and at home to Braga, the latter after taking a 2-0 lead.

Fischer said he felt supported by the club despite the dry run and backed his team to return to form.

"We've achieved our goals and celebrated successes together in the past few years.

"Now it's a little stormy.

"I'm not worried about what might happen in two, three weeks -- I'm concentrating on the here and now.

"Our task is Napoli."

Midfielder Rani Khedira, who made his first start of the season on Saturday after returning from injury, said the scale of the encounter meant his team were up for the task.

"It's a Champions League game against a very interesting opponent, so the mood has to be good automatically, even if things are a little complicated for us right now."

While star Napoli striker Victor Osimhen will miss the clash with a hamstring injury, Fischer warned of forward Khvicha Kvaratskhelia, who scored a double in the Italian side's 3-1 win over Hellas Verona on Saturday.

Fischer would not be drawn on whether nine-time Serie A champion Leonardo Bonucci would start the game, the Italian captain having spent Saturday's 3-0 loss to Stuttgart on the bench.

The coach did however reveal that Germany defender Robin Gosens was "under treatment" for an injury ahead of the game.

Gosens has been a rare bright light for Union this season, impressing since his move from Inter Milan in the summer.

"But I'm really positive things will work out with Robin tomorrow."