Jurgen Klopp was proud of Borussia Dortmund's response following the attack that hit their team bus ahead of the Champions League meeting with Monaco on Tuesday, though he initially feared for his friends at the club.
Dortmund players and staff were caught up in three explosions as they made their way from the team hotel to Signal Iduna Park for the first leg of their quarter-final.
Marc Bartra was hospitalised as a result and had surgery on a fractured wrist, with the teams instead playing on Wednesday – a decision both sides have been critical of, though UEFA denied receiving information that the players were against the rescheduling.
Liverpool boss Klopp, who won two Bundesliga titles and was a runner-up in the 2012-13 Champions League during his seven years in charge of Dortmund, admitted it was difficult to see how a club and players he knows well were affected, though he could understand the decision-making process on the UEFA side too.
"Everybody can imagine it was a difficult moment for me because I don't know how often I was in the team hotel with Dortmund," he said. "I know exactly the road. A lot of my friends were in the bus. I was really concerned, scared for them.
"In the first moment it looked like a bit of relief and it was not too serious, then the more info you got the more serious it got and that was really difficult.
"I had contact with people, but I didn't want to bother them with my silly questions. I was waiting like the rest of the world for more information. The last thing I thought about in this moment was the game actually.
"I watched the game yesterday and I can 100 per cent understand both sides, how it was difficult to find another date in this really tight schedule. But of course, I think everyone would have understood if we said okay, we don't play it.
"I saw the game and I was really proud of Dortmund. They created this atmosphere, but they tried to be at their best and after the game I saw the faces of the players and I saw the shock in their eyes and that was really hard.
"It will take time to deal with it in a proper way because I'm pretty sure if somebody who made the decision afterwards had been in the bus they wouldn't have played the game.
"If you weren't in the bus I'm sure you can't imagine how it was. But the game is over, it's done. They have a few days to, what can I say, to try to learn to live with it."
Dortmund lost the match 3-2 and play Eintracht Frankfurt in the Bundesliga on Saturday before the return leg in Monaco on Wednesday.