I remember that song, though admittedly not quite the first time round as I was only 18 months old by the end of the '60s! But I often get random bits and pieces like that where certain bits of a piece of music, whether the music itself, the arrangement or just the overall "vibe" remind me of something else. Sometimes it's intentional, sometimes not.
I am very impressed with Borislav. I thought Kirill would be an impossible act to follow, but Borislav does his own thing while still managing to be a worthy successor.