Just like what Hiro said, he needed to pull his shit together and stand. He needed to apologise to his teammates for failing them.
Yeah, it wasn't his fault that they conceded the goal. But he couldn't still deny that his inability to stop the goal was one of the factor which led to this disaster.
If he wanted to evolve then he needed to become responsible for his actions. And there's no denying to the fact that he was beaten miserably by the opposing team. It was his utter loss.
If only he could defend better. If only he could react better. If only he could be more reliable then there wouldn't be such situation.
At once, waves and waves of emotions started rising within Shun's heart. Eventually his guilty concise made him purse his lips tightly and become angry at his own pathetic self, 'Just trying isn't enough...'