Ben Lee's tactical analysis of Tuesday's game: https://www.pinkun.com/news/23340854.norwich-city-tactical-analysis-birmingham-championship-cruise/
That helps to explain the difference between the two halves. Wagner is searching for solutions and the improvement in both Sara and Nunez is making our midfield more dynamic and more effective. That showed again against Cardiff with Sara moving to the fore that game. Millwall will be a real test of this and Marquinos' adjustment to the Championship. There is clearly a chemistry between those three which will hopefully develop further.
