The Citizens have qualified for the semi-final of the Champions League for the second time in their history, and Guardoila says he is excited for all those involved with the club.
City went into the second leg having to protect their 2-1 lead in the first leg, but Dortmund took the lead through Jude Bellingham in the opening 15 minutes.
The visitors got their equalizer ten minutes after the break through the penalty spot thanks to Riyad Mahrez, before Phil Foden’s belter put the Citizens through to the last four on 75 minutes.
"I am incredibly happy for this club, for this chairman and for the fans, everyone,” the former Barcelona and Bayern Munich coach told BT Sport after the game.
"It is the second time in the semi-finals so it is not history in the club, but we start to build it.
"We were brilliant except the first 10 minutes where they were good.
"I'm incredibly happy to be in the semi-finals, to be one of the best four teams in Europe, to be against big, strong teams and we will try to be good."
Manchester City and Guardiola have been deemed failures in Europe, having failed to go past the quarter-final stage since the Spaniard took over as head coach.
He added: “This competition is nice but also so unfair because we are judged as a failure or a disaster when we are knocked out. You play 11 months for the Premier League and the other competitions.
"Today it was a penalty with the hand and maybe not given on another day it could be not given. We were out for handball when it was not given against Tottenham. This competition depends on the situation. But the way we played in the second half was with personality."
