Koke's goal secured a 2-1 aggregate success against Barcelona last night that put his side into the last four of Europe's elite club competition for the first time in 40 years.
The stunning 1-0 victory at an electric Vincente Calderon followed last week's 1-1 draw in Barcelona in their Champions League quarter-final, first leg, and denied Barca a record-extending seventh consecutive appearance in the last four.
Even the loss of Diego Costa, the talismanic madman, before the game to a hamstring injury was not enough to halt Diego Simeone's relentless pack of harriers.
A fired-up Atletico blew Barca away in the opening 20 minutes and after midfielder Koke - for his first goal in the Champions League - volleyed in from close range in the fifth minute, former Barca forward David Villa twice hit the crossbar. "It was a very important goal because it got us through to the semi-finals," Koke said. "The work of the team across both legs was spectacular.
"We ran a huge amount, we played the two games in the way we wanted and I think we were the clear winners. With these fans it is very hard for us to lose a match here."
Barca showed more intensity and had their chances in the second half against an exhausted Atletico but the home side held out with inspirational coach Simeone willing them on from his technical area.
In the end, it was a familiar story for Barcelona over the past couple of years: pass, pass, but no penetration and useless defenders. Questions will surely be asked of Gerardo Martino's tactics and the ineptitude of Cesc Fabregras, in particular.
"We had the game within our grasp," Xavi, the Barcelona midfielder, said. "We had four or five very clear chances that normally we would put away.
"They made the most of those first 15 to 20 minutes when they played with a lot of intensity and scored the goal. We played two good games and had our chances but it slipped through our fingers."