Bale, 29, netted a spectacular striker in the 2018 UEFA Champions League final against Liverpool to give Real the lead before their eventual 3-1 victory.
However, the Wales all-time record scorer missed out on the FIFA Puskas award to Mohamed Salah, for his solo effort in the Merseyside derby.
"Yeah, I was surprised by that, to be honest. What can you say? It makes the award look a little diminished, although it was obviously a great goal by Salah," Bale told FourFourTwo.
The four-time UEFA Champions League winner further explained that he knew the ball was heading for the back of Loris Karius' net as soon as he met it with his left foot - and described it as the best goal of his career thus far.
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"It was instinctive," he said. "I got my body positioned correctly, got my footwork right, and caught it perfectly. When you catch the ball perfectly, you know it's on target.
"You just have to hope the keeper doesn't make an unbelievable save. So as soon as I hit it, I knew it had a chance of going in. If you watch it, you see my head turn straight away. I knew where the ball was going.
"I think you'd have to say that [it was my best goal]. There haven't been too many like that! I did love the one in the [2014] Copa del Rey final against Barcelona, but as this one was on such a big stage – the Champions League final, the biggest game in club football – and technically it was the winner, I'd have to say that it's the best."