The Chilean opened the scoring early for the Gunners, but did the referee miss two infractions in the build-up to the opening goal at Wembley?
Arsenal took a controversial 1-0 lead within five minutes in the FA Cup final on Saturday and Twitter was ablaze with anger at the referee's decision.
Alexis Sanchez finished low past Thibaut Courtois to give the Gunners the perfect start, but he arguably could've been whistled for handball, or Aaron Ramsey for offside due to his position behind the defenders.
The Chilean appeared to block a Chelsea clearance with his arm before Ramsey, in an offside position, briefly made a play for the ball before backing off and allowing Sanchez to take the ball from an onside position and score.