Pep Guardiola welcomed the show of support for Oleksandr Zinchenko as the Ukrainian defender captained Manchester City in their FA Cup win at Peterborough United.
With his country experiencing a Russian military invasion, Zinchenko stepped up to assume leadership on the football pitch after being handed the armband by Fernandinho.
It was a move designed to show solidarity with the 25-year-old as he waits for news from what Guardiola described as "this nightmare" in Zinchenko's homeland.
"It's not an easy period for Oleks," Guardiola told a news conference. "His family, his country, but playing football is the best for him at the moment."
In a separate BBC interview, Guardiola said of the left-back: "Unfortunately his citizens in Ukraine are living in a terrible and crazy and insane situation. All the people here at Peterborough, not just our fans, showed him warmth.
"Hopefully this nightmare can finish as soon as possible."
Goals from Riyad Mahrez and Jack Grealish in the second half carried City through to the quarter-finals.
Both were set up by Phil Foden, whose pass to Grealish for City's clincher particularly caught the eye.
Grealish later revealed it was inspired by watching clips of Guardiola's former Barcelona charge Lionel Messi in action.
"The pass from Phil was excellent. It was quite similar to the pass from Phil that he did to Joao [Cancelo] in Brugge in the Champions League, and the control was excellent from Jack," Guardiola said.
The City boss added: "They were brilliant goals. The quality for Riyad and the second goal the same. It was good.
"We created chances. All of them were brilliant. Riyad always had this quality in the final third – he is the best player in the final third that we have. He scored a fantastic goal. I'm so proud for the game he played."
There was cause for slight concern ahead of Sunday's derby against Manchester United, with Guardiola substituting starting centre-backs Ruben Dias and Nathan Ake at half-time due to what he hopes are only minor knocks. Aymeric Laporte and John Stones proved capable replacements.
The City manager said Dias was "not feeling good in his leg", while Ake suffered a blow when committing a first-half foul.
"That's why, for caution and to be alert, we made the substitutions," Guardiola said. "It was not planned. I would say it was a medical decision."