1. There's no cheating or attempt at cheating at all.
2. Almus was mostly on defensive the whole fight, observing how Rigar fight and basically conclude that: Rigar is so used to winning just by his blessing's power that his actual skill is pretty trash, in fact King Fermes would likely win against him.
As the fight goes on, the spectators thing that Almus was getting pushed, but in reality Rigar is the one running out of breath.
At which point Almus casually turn to the judge (Yuria) goes "watch closely Yuria" and give her a wink.
That enraged Rigar and made him charge in.
Almus deflected his blow to the side, causing him to fumble to the ground, and Almus goes for a diagonal slash.
Rigar finally click that he's about to get CHOP'd and surrenders in panic.
The cut sliced through Rigar's sword, and stopped right before it cut his neck.
Yuria then declares Almus the winner.
After that Almus was like "oops, if only I'd just kill him then pretty much all the problems would end right there" (i.e. he stopped the swing after hearing Rigar's surrender and not because he planned to let him live from the start)
And then he notice the state of Rigar and that the latter pissed his pants and decide he'll pretend he didn't see that out of pity.