I only watched the first half, and due to the tight camera views, I have to guess at what was happening away from the ball by the absence of players near the ball. What I think Senegal was doing was defending in a 154 shape, with the lone forward putting pressure on the ball. The 5-man second line put 3 defenders in the center in order to outnumber our players in the center, which I think allowed them to win the midfield battle. In the half I watched, I didn't see any coaching adjustments. To my eye, our U17 players appeared to have better fundamentals than our senior players. If the coach made no adjustments at halftime, I would be concerned.