Support during slumps

As any athlete knows there are times when we go through slumps... I have been there. But how do you support your child when they experience slumps. My son had a game today they got blown out 22 -10 before halftime the score was 16 -0. Before game it was somber because my son hasn't been at practice due to illness, so pre game I just gave him a few things to work on, so he would feel calm. He rebounded well had 6 rebounds. During game its important to stay positive and focus on reinforcing his/her motivation.... after game just hug them and support them and if the game was less than stellar focus on highlights!