Mats Hummels was reminded of the atmosphere during Germany's friendly against France that took place amid November's Paris terror attacks when he captained Borussia Dortmund to victory over Mainz in the Bundesliga on Sunday, a game during which a home fan suffered a fatal heart attack.

The crowd inside Signal Iduna Park became subdued as the news spread, overshadowing the action on the pitch, which had seen goals from Marco Reus and Shinji Kagawa secure the points for the hosts.

Another supporter was rushed to hospital and in a statement after full-time, Dortmund confirmed: "There have been two tragic incidents inside the stadium during the game. Unfortunately, one of the people did not make it and passed away. We have been informed that the second person's situation is stable."

Hummels conceded the feeling for the players on the field – sensing unease among fans without knowing exactly why – was similar to the one he experienced playing for Germany as the Stade de France was targeted by suicide bombers as part of coordinated attacks that claimed 130 lives.

"It was certainly not an everyday [atmosphere] – quite the contrary. This is something I've experienced only in Paris," Hummels told Kicker.

"The atmosphere was somehow a bit quiet, some turmoil was felt. It was quite strange. After the game we were informed directly, but it was clear something must have happened.

"You notice it and it is not easy to uphold your concentration in such an unusual atmosphere. We have done well [to win the game], although that is not the main theme."

Supporters sung the anthem 'You'll Never Walk Alone' during the match in tribute to the fan who passed away and the Dortmund players then stood before the crowd for a poignant rendition after the game.

"Definitely, a great compliment is due to the fans. It was entirely appropriate to [sing]," Hummels added.

"It is difficult because they are supposed to cheer heartily. With the song 'You'll Never Walk Alone', they have shown a very, very good response."