What happened: Sean Sheehan argued the penalty Sunderland were awarded against Arsenal was not a genuine foul, while a separate legitimate penalty went uncalled in the same match. Arsenal are set to contact referees' chief Howard Webb and the Professional Game Match Officials Limited over the decision.

Why it matters: The dispute adds to a run of Premier League officiating complaints this season. Arsenal escalating the call to Webb and PGMOL directly, rather than letting it pass, signals the club is treating it as a review case rather than a routine gripe.

What to watch: Watch for Arsenal's formal inquiry to PGMOL and any response or review outcome from the officiating body.