Press Association Diego Costa once more proved to be the scourge of Arsenal as Chelsea left the Emirates Stadium with a 1-0 victory. The 27-year-old, who was frequently booed on Sunday by Gunners fans following his antics at Stamford Bridge in October, was again in the thick of the action and his strike proved to be the difference between the two teams. Here Press Association Sport assesses the striker’s contribution. HISTORY REPEATED Costa’s performance in September’s reverse fixture – when he antagonised Gabriel into a red card – was lauded by Jose Mourinho and labelled “unacceptable” by Arsene Wenger. This time in opposition it was Laurent Koscielny and Per Mertesacker, who soon saw red for a trip on the striker. “Diego Costa, he’s done it again,” sang the visiting supporters. RIVALRY The Brazil-born Spain striker showed his bad side when he petulantly placed a foot on Aaron Ramsey after both went to ground in the second half. He was booed at every opportunity by the home support, who jeered and hurled insults at a tiring Costa as he was replaced by Loic Remy with 22 minutes remaining. GOAL THREAT Costa caused confusion between Mertesacker and Koscielny to create an early chance for Oscar. He then tried to reach Willian’s through ball in the move which led to Mertesacker’s dismissal. Next he stunned Arsenal with a fine near-post finish from Branislav Ivanovic’s cross before being denied by Petr Cech after beating Nacho Monreal. OVERALL IMPACT Arsenal manager Wenger encouraged his players not to get involved in any antics with Costa, who was told to concentrate on football by Chelsea interim boss Guus Hiddink. Costa did as his boss instructed and now has six goals in six games since Boxing Day; he had seven goals in nearly 11 months prior to that. He also has two goals against the Gunners in three games and has drawn two dismissals.