OK, I never coached but read all the books and been on the coaches bench for a few years with a 30+ year coach. I enjoyed learning. Definitely defense. He had little hope for a player that was all offense and could not defend, and built his state, region, and club champions around defense. A case in point, in club, he had the Georgia HS scoring leader, who then went to SEC D1 and was the SEC Freshman scoring leader. She was unstoppable in club and would only play half a match to keep from running up the score, and the only drills he would usually have her run in practice were defensive drills. He always said defense controls the speed, timing, and strategy of the match. In the Georgia State Cup he used 8 girls (rest had flu) in a Catenaccio, to hold off the #1 R3PL team for 60 of 90 minutes to zero goals. I am still impressed by that.
