A few years later, the answer revealed itself to me. If you look at this image, it was not that difficult to guess how I got this Dragonfly in Flight photograph. It was so simple, so easy, that sometimes we seek answers at all the wrong places. Note that I was using Single-AF, not continuous.
Image taken with Olympus PEN E-PL7 and M.Zuiko 45mm F1.8 lens.
Well, I could have said along the lines of "OMG the E-PL7 has improved Continuous AF that it can track flying insects!". That was the exact same thing that the friend did years ago, with his system.
I guess those who have shot enough dragonflies will know the answer. I shall keep it open for you to guess, if you have not already known it!