Chelsea's 6-0 demolition of Arsenal at Stamford Bridge on Saturday sent shockwaves across the league, ruining a landmark occasion for Arsene Wenger and it also had a drastic influence on the Premier League title race. Samuel Eto'o opened the scoring before Andre Schurrle doubled the advantage moments later. Then, a bizarre incident of refereeing saw Kieran Gibbs dismissed, when it should have been Alex Oxlade-Chamberlain, and Eden Hazard dispatched the resulting penalty. A brace from Oscar and Mohamed Salah's first Chelsea goal finished off the Gunners. The match was Arsene Wenger's 1,00th in charge of Arsenal and he was looking for a result, potentially his first win against Jose Mourinho. However, what he actually got was a horrific display from the Gunners since the first whistle was blown and Arsenal were swept aside with ease. Chelsea are now looking in good form for the Premier League title, while Arsenal are now seven points off the pace. The game taught us many things- here's the five most important that we learnt.