The 22-year-old midfielder's early volley proved enough for Atletico to win 1-0 at the Vicente Calderon and go through 2-1 on aggregate, reaching the semi-finals of Europe's top club competition for the first time in 40 years.
"It's spectacular," Koke said. "This team has no limits."
Koke is aware how crucial his contribution was, but modestly deflected praise to his team-mates.
"The goal was very important because it helped the team to move on to the semi-finals," he said.
"But the work of the team in this tie has been spectacular. We are clear winners. I think with (fans) like this it's very difficult to lose a match."
Atletico will go into Friday’s last-four draw in Nyon alongside Bayern Munich, Chelsea and Real Madrid, and while Koke accepts all three would be a big challenge to Diego Simeone's team, he believes they may have knocked out their toughest opponents.
"The next team we will play will be very tough," he said.
"But we have eliminated one of the best, if not the best. Let's make the people keep dreaming."
Defender Miranda, who helped Atletico keep their fifth clean sheet in seven matches in all competitions, attributed the victory to the tactics of Simeone and the incredible atmosphere at the Vicente Calderon.
"It was a great game," the Brazilian said.
"Barcelona are a great team with so many great players, but I think our tactics were right and helped us win the game. We were organised.
"The atmosphere was really special. It drives you on. The fans played a big part."
