I have a slightly different spin on the tactical changes with subs. Clearly the tactics in the match shifted as we played deeper and hoofed it to Benteke more, but I don't think it was adding Benteke or Bacuna or grealish that cased it. It was pellegrini's move to pull of dzeko, and put on a midfielder. Previously, Delph, cleverly, and Westwood had numbers there. The extra midfielder took that numerical advantage away and forced Bacuna and grealish to drop a bit to help. This left Benteke even more isolated, so hoofing increased. It also decreased the short pass outlets, encouraging us to play it long. Just my opinion.