Well you see, no way was Eder Gonzalez NOT the better man when he officially lost to Juan Coggi the first time, because that was not a fair loss. He KO'd Coggi like 3 times, but the referee was so disgraceful that he got banned for life. Gonzalez officially lost, but he was the better man in the ring that night. Tyrone Everett officially lost to Alfredo Escalera, but he was the better man in the ring that night, winning 10 to 11 rounds. But let's say a fighter is doing well on points, but loses fairly. He quits or can't continue because his face is cut to shreds.
There was talk that Floyd should have lost his fight with Zab because Roger entered the ring during the fight, which is normally a disqualification for the fighter. Had Floyd been disqualified in that instance, I guess that would have been a fighter losing fairly (according to the rules) but being the better man in the ring. I'm reaching.
Not always, hopkins lost the first fight to taylor but I don't think anyone will say that taylor was the better fighter even in that fight.
Thinking more yes there are many cases that the better fighter looses fairly because someone out works or has more determination to win.