Arsenal were victorious in their home match against Chelsea. From the first minute, the home team looked the more dominant side. For once, Unai Emery seemed to understand how he should line his side up in the Premier League, and started with a 4-4-2 which worked from the start till the end of the match.14 minutes into the derby, Alexandre Lacazette opened the scoring. Despite Chelsea's dominance on the ball, they hardly created any chances for themselves. Eden Hazard was once again playing as a false number nine in the middle, with Pedro and Willian supporting him. However, Arsenal's centre-backs knew exactly how to deal with the threat that Hazard posed. More chances fell to the Gunners, who doubled their lead through Laurent Koscielny. Koscielny made numerous vital blocks in his own box to help his side keep the clean sheet. It had a long time since Leno had kept a clean sheet.The second-half passed without many notable events. Arsenal could have scored more goals to seal the result of the match, but as Chelsea dominated the ball, Arsenal had to defend. Although it was a joyous evening for the Gunners who pocketed three points and remain in contention for the top four, Hector Bellerin was stretchered off after a knee injury in the second half.The Spaniard had just returned from injury, and he barely lasted a match before he suffered a nasty looking knee injury. Unai Emery will now have another headache as Ainsley Maitland-Niles and Stephan Lichtsteiner clearly do not possess the attacking instincts that Bellerin has.Maurizio Sarri looked disappointed to see his side fall. In the second match of the season, Chelsea had beaten the Gunners at Stamford Bridge in an unconvincing fashion. Now, the Gunners have exacted revenge on their opponents. Nonetheless, Arsenal fans were elated to see Mesut Ozil back in the squad even though he did not get any game time, and that the club won the London derby in great fashion, just in time for the FA Cup clash against Manchester United next weekend. Here was how the fans reacted to the game.Laurent Koscielny’s game by numbers vs. Chelsea:100% tackles won13 clearances3 interceptions2 shots on target1 clean sheet1 goal A masterclass from the Arsenal captain. 💪 pic.twitter.com/AIpndMuLtb— Squawka Football (@Squawka) January 19, 2019"Arsenal's organisation was the thing that impressed me most this evening."- Rio Ferdinand pic.twitter.com/BySLbo58J6— AFTV (@AFTVMedia) January 19, 2019Most shots in target in a Premier League game under Maurizio Sarri: 11 vs. Arsenal at home.Fewest shots in target in a Premier League game under Maurizio Sarri: 1 vs. Arsenal away.He who laughs last... pic.twitter.com/ohfofW4t2v— Squawka Football (@Squawka) January 19, 2019Arsenal 2 Chelsea 0 - Talking points:-Today we saw shades of prime Koscielny-Bellerin top 5 right back in the world -Lacazette the big game player delivers again-Ramsey so crucial over the next few months-Diamond the way forward-Guendouzi's best game in an Arsenal shirt— LTArsenal™️ (@ltarsenal) January 19, 2019Arsenal blow Sarri-ball away 🔫 pic.twitter.com/8c9m59koCJ— B/R Football (@brfootball) January 19, 2019Arsenal fans seeing Man United win 6 premier league games in a row, only to move from 6th to 6th position. pic.twitter.com/lOyehH9dI6— Troll Football (@TrollFootball) January 19, 2019I’ll count three points here already. Perfect first half, second was just finishing the job. Why can’t we play week in week out like that. We need more consistency @Arsenal— Lacazettes (@Lacazettes) January 19, 2019Arsenal defeat Chelsea 2-0 and London is red! pic.twitter.com/be6w2oy1u3— NBC Sports Soccer (@NBCSportsSoccer) January 19, 2019Alonso Can’t Defend ❌Can’t Attack ❌Can’t Overlap ❌Can’t Track Back ❌Can’t Cross ❌Arsenal’s MOTM #CFC— CFC Daily (@CFCDaily) January 19, 2019Chelsea failed to register a single shot on target in first half against Arsenal Maurizio Sarri will have to smoke an entire chimney of cigarettes to get the Premier league right 😂😂😂#ARSCHE— Pye Waw (@pyewaw) January 19, 2019Alexandre Lacazette record vs the top 6 since signing for Arsenal:Vs Manchester United: 1 goal, 1 assistVs Chelsea: 1 goal, 1 assistVs Liverpool: 1 goal, 1 assistVs Tottenham: 1 goal, 1 assistVs Manchester City: 1 goalBig. Game. Player.— Patrick Timmons (@PatrickTimmons1) January 19, 2019So we can’t even score a goal against this shit Arsenal defense? OMG we’re so bad.— Ali🇬🇭 (@TheBeardedRauI) January 19, 2019Arsenal have 99 problems but Chelsea ain’t one.— Lacazettes (@Lacazettes) January 19, 2019Great win @Arsenal much needed 3pts #Top4finish— Ray Parlour (@RealRomfordPele) January 19, 2019