In a whirlwind second 45 minutes, Hector Bellerin went from being the harbinger of Arsenal's downfall to their eventual savior thanks firstly to his reckless challenge on Eden Hazard to give away a penalty and secondly to his 92nd minute equalizer to earn a draw against Chelsea.Arsenal had taken the lead against their London neighbours thanks to a fine second-half goal from midfielder Jack Wilshire - a beautiful moment for him following his injury issues - before Hazard's penalty levelled things up.Bellerin lunged at the Belgian and to Arsene Wenger's dismay, Anthony Taylor pointed to the spot to give a penalty in consecutive games to the opposing team playing the Gunners. Hazard sent his penalty to the left, beating Petr Cech, and evening the away sides deficit.Chelsea began to show the depth that has helped them to 3rd position in the league, with full-backs Davide Zappacosta and Marcos Alonso linking up wonderfully to tear apart Arsenal's makeshift defence for Alonso to put Antonio Conte's side ahead.For the final goal of the game, it was the story of two full-backs who had featured prominently, except with their roles reversed. During a desperate search for a goal, the ball found its way into the Chelsea area, where it was only half cleared by goalscorer Alonso - into the path of the onrushing Bellerin, whose driven half-volley was still rising when it hit the net. Redemption.Following the late, late goal, Arsenal did everything they could to throw away their lead once more. Straight away, somehow - and not for the first time - Alvaro Morata found himself one-on-one with Cech. In this position, the Spaniard striker was definitely the favourite to find the net, but Cech did extremely well and had fantastic composure to prevent the strike from finding the net, with the rebound then falling to Zappacosta, whose effort then hit the crossbar. Full-time, and somehow Arsenal kept a point.At full-time, Wenger, like his side's supporters, looked like he had really been put through the ringer. Looking absolutely drained in the post-match press conference, he highlighted that the game that had just been played in front of us was a terrific game of football - and it's difficult to argue with him there.He then addressed a bug-bear that has long-hassled him and always looked like it may have a part to play in this match following the outrage of the West Bromwich Albion game on New Year’s Eve - refereeing decisions.To be fair, in this tie, the refereeing decision of Taylor was not anywhere near as controversial as Mike Dean’s last minute call in the previous game, so while Wenger may feel hard done by, it was probably the correct decision.The makeshift defence of Calum Chambers, Shkrodan Mustafi, Rob Holding, Bellerin and Ainsley Maitland-Niles did well during the first half especially to prevent goals, but Chelsea really should have found the net through Morata on more than one occasion, who wasn't really at the races on the night.Within the first 15 minutes, he managed to find himself behind Chambers and Mustafi following a hopeful belt up the field from Victor Moses to leave himself with just the keeper to beat, but botched his side-foot finish. He would do this again following Wilshire's goal from a tighter angle, but still a glaring missed opportunity.This result means that Arsenal remain where they were before the match - 6th place on 39 points, one behind Tottenham Hotspur, who play tonight against West Ham United, where a win will extend the gap between Arsenal and Champions League positions, with Liverpool in 4th on 44 points. Chelsea remains in 3rd place on 46 points, one behind Manchester United.Fans are really getting their money's worth in goals at Premier League matches in the Emirates at the moment, aren't they? With the exception of the Newcastle United 1-0 victory in December, there has been at least 4 goals per game since the 5-0 win against Huddersfield on the 29th of November. Sadly, while goals have been guaranteed, wins have not, with these games including the loss against Manchester United and draws against both Liverpool, and last night, Chelsea.And, after being drawn to play each other in the two-legged League Cup semi-final, Chelsea will be returning to the Emirates later this month - but not before Wenger and his side make their way to Stamford Bridge on the 10th of January for the first leg.Amazingly, last night was the 6th time the two sides have played each other in the past 11 months across a number of different competitions, with the scoreboard now sitting at 2-2-2, with wins/draws/losses all equal. Perhaps the Cup games will give a winner in this imaginary London Derby tourney.Who knows what the Arsenal team will look like by the second semi-final fixture, with an increasing number of injuries (although Olivier Giroud and Aaron Ramsey should hopefully be fit by then) and the January transfer window to contend with.Was this Alexis Sanchez's last match in an Arsenal shirt? Will Mesut Ozil never return to play for the Gunners? I would be inclined to answer "no" to both rhetorical questions, simply due to the influx of matches yet to be played in January, but it seems certain some decision will be made on their futures before too long.Next up for Arsenal is the 3rd Round of the FA Cup, where they will compete with Nottingham Forest as they begin their defence of the trophy they won against Chelsea in 2017. A different look team will no-doubt be contesting the match on Sunday the 7th of January, with Wenger likely to give some youngsters an opportunity in the cup in an effort to blood them and rest some senior players that have played a great deal of football in the last month.To have the last word on this league match, a draw in the circumstances wasn't the worst result. But even with that being the case, upcoming games against Bournemouth away and Crystal Palace at home need to be victories or the league season may be close to disrepair.