Those early season thoughts that Chelsea might be the team best placed to challenge Arsenal are beginning to look over-optimistic. The two chaotic wins with which they began the season were always difficult to read: they might have been useful points picked up on the way to a more solid structure, or they might have represented evidence of significant problems. After three games without a win, it’s beginning to look like the latter. Brentford’s first home win over Chelsea since 1938 means they…