“Evolution never stops. As the World Cup showed, 4‑2‑3‑1 has come to replace 4‑4‑2 as the universal default (18 of the 32 teams played some form of 4‑2‑3‑1 at some stage, with another three fielding a 4‑4‑2 that perhaps should have become 4‑2‑3‑1) so the system at the very highest level has already begun to mutate. Spain, by the end of the World Cup, had followed what Barcelona did at times last season, what Arsenal seemed to be reaching towards, and set up in a 4‑2‑1‑3.” (Guardian)