Both of these ideas can be debated widely.if you have fitteset and strongest body but mentally week,that might lead to failures,cause an individual might loose their confidence and have too much stress which this can change the results.on the other hand if a person mentally strong and stable but physically weak , that might lead towards imperfect results.besides this situation will changes in the sense that if it's a solo player or it's a team .I believe that when you're in a team the mental status is more important.a team player who has a better mindset and can focus and think fast work better in a team meanwhile this person isn't the fittest or strongest .it can be beneficial for the team in a certain ways which lead the team to victory .on the other hand this situation is different in a solo player.in fact there's more pressure both mentally and physically on a solo player .cause no one is there to cover his imperfections.