Neymar inspired Barcelona to an unbelievable comeback, the Brazilian scoring twice as his club overturned a 4-0 first-leg defeat in style thanks to Sergi Roberto's injury-time winner.
Guardiola won the Champions League title twice with Barca, in 2008-09 and 2010-11, and while he could not watch the 6-1 victory as he was managing City to a 0-0 draw in the Premier League, he praised the LaLiga giants.
"I'd like to congratulate Barcelona, it’s an amazing result they got tonight," said Guardiola after his side missed the chance to narrow the gap to leaders Chelsea to eight points.
"It is incredible and I celebrate it especially for Luis Enrique. Also for this generation of players, who are doing so many good things. I am curious to see the game repeated, calmly, when I have time."
In contrast to the Camp Nou goalfest, with Barcelona 6-1 winners on the night, it was a tale of frustration for City, who would have moved above Tottenham into second with a victory, and Guardiola accepted Stoke City made it hard for his team.
"They defended deep and it was complicated to find the players between the lines," Guardiola said. "We were there in the last minutes. I don't have regrets about how they ran, how they fought.
"It’s not easy when the opponents are there. We created a lot of situations for the last pass and sometimes we missed it. When [David] Silva came in, we created a few more chances. When you analyse the chances we had, I don't really remember more than one Stoke chance."
Guardiola gave Raheem Sterling the night off and Silva started on the bench as City plan ahead for an FA Cup tie against Middlesbrough and a second-leg Champions League last-16 meeting with Monaco and the manager said he will continue to make changes.
"We have to make rotations when we play a lot of games. The gap [to Chelsea] was big and is still big. We have to focus game by game."