Napoli's Giacomo Raspadori scored a second half goal to secure a 1-0 victory at Union Berlin in their Champions League Group C match on Tuesday and stretch their opponents' losing run to nine straight games in all competitions.

In a match that had few highlights, the Germans enjoyed the better chances in the first half but it was a run by Napoli's Khvicha Kvaratskhelia down the left that decided the game as he set up Raspadori to fire home the winner in the 65th minute.

The result kept Napoli in second place on six points, three behind Real Madrid who won 2-1 at Sporting Braga.

Braga are on three while struggling Union are still without a point in their first season in the competition.

"It wasn't our best game technically, but winning this kind of game is important," scorer Raspadori said. "They were well organised and had prepared for the match very well.

"We knew it would be difficult and we saw it on the pitch. I believe we could have done better, but an away win like this in the Champions League is always good. Playing in the Champions League and scoring is fantastic," he said.

Napoli initially had most possession but Union, desperate to end their losing streak, tried to hit the Italians on the break in the first half through Brenden Aaronson and David Fofana.

The latter, who had an effort saved, also put the ball in the net in the 24th but was ruled offside.

The visitors, without injured striker Victor Osimhen, struggled to break through a solid backline until the Germans repeatedly failed to clear the ball in the 65th.

Kvaratskhelia got possession, turned on the turbo to charge into the box from the left and cut the ball back for Raspadori, who had no trouble beating goalkeeper Frederik Ronnow.

Union, who have now lost their last six league and three Champions League matches on the trot, had no comeback in them despite coming close with a Robin Knoche header in the 81st.

"The first half was courageous and very good from us," said Union captain Christopher Trimmel. "It was a good step in the right direction. Yes we lost but overall delivered a good game."

The frustration of a third straight loss in the competition was evident, however, when Fofana was substituted but refused to shake the hand of coach Urs Fischer, who is under mounting pressure.