Siberian is right. He only built one Grenadier out of his Krieg Barracks. That one attack, where you got these massive amount of kills with grenades, gave Siberian 2 free Gren squads. The attack after that, gave him another free grensquad. That medic bunker won the game here.
But if you watch it game you will see that i had only 3 volks and 1 inf squad. The rest give me med bunker with your help.