Ahh, a probability person!
With 60% chance of winning, probability of losing twice in a row is 16% (i.e. 0.4x0.4) and at 6.4% for three losses. Unprobable, but I accept that it can happen. However, a little bit of code to throw in a difficulty factor at particular rounds based on specific (or random) player profiles would boost up the chances of losing. This one is minor, but I've had plenty of occasions when I've lost anywhere from
10 to 20+ times on particular rounds significantly against the odds.
The most recent was two tournaments ago in round 27 against Mercury L19 where my Diamond type dragons (i.e. Diamond, Infinity, Valiant, etc.) had a 45% chance to win in each battle. On this occasion,
I incurred 14 straight losses before taking it down on the 5th attempt of using Infinity L15 at attempt 15. Probability of losing 14 straight times was supposed to be POWER(0.55, 14) = 0.023%! In the same tournament against Nyx L20, I lost 5 straight times using dragons with 55% and 45% chances of winning; probability of losing 5 straight times was supposed to be 0.45*0.55*0.45*0.55*0.55 = 3.4%.
Pretty much at least one out of every three tournaments, I have encountered a dragon where I would experience 10+ losses before "randomly" taking it down. Hence, it would be reasonable to conclude that something else is at play (aka "rigging").