Bale, who moved from Tottenham to the Spanish capital in 2013, played a key role in getting them closer to their 11th European title, as his shot deflected off Fernando past Joe Hart.
The Welsh star will play in his second Champions League final for the club in under three years – he scored against Atletico in the 2014 final.
Bale told talkSPORT: “It’s massively important.
“Whoever got the goal tonight, whatever it was – the most important thing is we got to the final.
“It was a very professional performance, we kept it tight at the back and did well to get the goal to take us to the final.
“Obviously we needed a bit of luck with the goal, but I felt like we controlled both games. Maybe they lacked a bit of ambition going forward but that’s down to us. We kept it tight and limited their chances and ultimately got the goal.”
On the final against Diego Simeone’s side, who beat Bayern Munich in the other semi, Bale added: “We know it’s going to be another difficult game, it always is against them.
“They make it very difficult to play against but it’s one we’re looking forward to – hopefully another trophy. We’re looking forward to it.
“It’s the main reason I came to Real Madrid – to win Champions League trophies. We’ve obviously won the most in the history of the tournament.
“To have another chance to win another trophy is amazing for us and hopefully we can take that opportunity.”
Gareth Bale was talking to talkSPORT after the Champions League win over Manchester City, listen in full above.