My guess is that he bet on the fact garv used sand dust and not dance of impetus (like actually was, since this is what the picture shows), and that he hoped to immobilize in round 2 minato with the chase triggered by madara founder mystery after that naruto popped the dodge, way undervaluing the level of damage minato + konan mystery would have delivered on him (if garv didn't misplay he put in queue minato mystery asap, selecting the target tagged by minato in round 1) and i guess kisame was faster than madara 5ks, managing to interrupt it in round 1 (i suppose for faster he meant naruto only).

That said even if the 220k didn't behave so and selected main, the outcome would have been the same.

Since round 4 onwards, regardless what happened in round 2 and 3 (unless there is some serious misplay on garv side), is a match between a 100 chakra konan and a selftacking atk/combo + first hit dodge hokage minato. 100% granted win unless the naruto is 20k+ power stronger than konan, because naruto simply never reduces cd (he just owns a +45% bonus if and only if uses mystery asap, that means to let konan be free to hit when her mystery is available, while konan with 100 chakra owns +100% and minato in round 4 has in the worst case 5 stacks of his selfbuff) while minato stacks attack and once every two rounds pops naruto dodge with his own mystery letting so konan hit him and reduce cd too.

Even if he manages to interrupt konan every time, minato in round 6+ is so stacked that almost flat out kills naruto by himself with his two unavoidable special attacks + standard attack once every two rounds.