Speaking to the media, Alonso said: "We were two goals down and we couldn't find our footing. It was a painful defeat, we must admit that we were not up to standard today. We had some shortcomings at some points and sometimes it's good to see our mistakes, and you can draw lessons for the future.
"We start a new age after a break, with fresh minds," he said. "We want to build a team that plays as a unit, with everyone playing together... We were one match away, and it's painful, and let's see what happens now."
When asked if PSG were the best team in the world, the Spaniard added: "I would say that, they have been playing together for years and play at a top, top level. They play together as a team and it is tough to play against them. For sure, this is a challenge for us to improve."