A good performance is a result, not a goal. People win championships because they prepared well, they were coached well. They win because they have the best facilities and environment to do so.
When a manager asks you to perform better, what does he or she really say? I think it's more like a question: "What should I do to make your performance better?" A manager, coach, facilitator, scrum master, whatever you call a manager these days is the only one responsible for your performance. A bit of talent helps ofcourse but without a facilitator that talent will never show.
A scrum master should always approach developers individually and try to make them better. The team should be more then the sum of the members, a good team can make outstanding performances, but only if they are coached right. Think of it as a football team, without a coach the best individuals will never win a world cup. But a mediocre team with a good coach can reach the finals. He will select individuals and put them on the right spots, he will train the team in what they do best. He can make the difference.
So as a scrum master you should find the talents of your developers and develop them. Develop the developers. Put the right developers together to make the team better then the sum of it's individuals. You need talented developers of all shapes and sizes. Train them like a football team and harvest the best result possible.
