After a Summer of preparation, Unai Emery will usher in a new era at Arsenal on Sunday afternoon when he sits in the dugout for Arsenal’s Premier League opener against Manchester City.Ever since it was announced that the Spaniard would be taking over from Arsene Wenger, it’s been leading up to this moment – and it’s as difficult of match as the league has to offer, so it will by no means be easy.City’s escapades last season seen murmurs of "the best team to ever have played in the Premier League” emerge, due to the way they dismantled their opposition with ease, seeing plenty of comparisons to Arsenal’s Invincibles along the way.While these comments dispelled a little towards the end of the season - following some losses to Jurgen Klopp's Liverpool both domestically and in the Champions League quarter finals - now a new rhetoric has emerged: if City win two leagues in a row, with the same simplicity as they achieved their first title under Guardiola, will they be the best team the league has seen? It’s an achievement that hasn’t been made in over a decade, when city neighbours Manchester United last achieved the feat, and that, accompanied with elusive European success, will be what Guardiola is hoping spur his side on this campaign.For Emery, it is an enormous trial by fire to face the reigning champions in his opening game in a charge of a new team, in an unfamiliar league and country, but the one aspect that could be worse is that the game is taking place on home soil, in the Emirates Stadium.The new manager may hand debuts to some of his Summer signings. The attacking personnel was often impressive under Wenger, but the defence needed a shake-up and that’s the first thing Emery did when he arrived at the club.It is likely new signings Bernd Leno and Sokratis Papastathopoulos will be introduced directly to the first team. The same can be said for Lucas Torreira, perhaps the Gunners most exciting signing, but due to lack of experience with the team it is unclear whether he will begin the game, or instead a more familiar pairing of Granit Xhaka and Aaron Ramsey will anchor the midfield.Up front, Emery’s big choice is how to utilize the two most expensive signings in the history of Arsenal football club, Alexandre Lacazette and Pierre-Emerick Aubameyang.With both vying for the role of striker - but unlikely to be chosen to play together up top - it is Emery’s decision to choose how to use the players and whether accommodations need to be made.In fairness, having two top strikers under your disposal is a positive headache, but also an important one to get right. Lacazette has had a very positive pre-season campaign, and dropping him would seem harsh, but Aubameyang was the Gunners best player in the second half of last season, usually playing alone up-front.If both players were to be played at the same time, it would likely see Aubameyang drop back to a wing position, and Lacazette occupy the front spot. However these players are played will arguably be the most interesting (and perhaps pivotal) part of Emery’s team selection. Keeping goals out against City’s considerable attacking talent really should be the prerogative for Emery in his first game, however.In terms of team news, Arsenal midfielder Ramsey is back in training after suffering a calf problem, but left-back Nacho Monreal is doubtful with a knee issue, wit his place likely to be filled by Ainsley Maitland-Niles.Sead Kolasinac and Laurent Koscielny are the other injury absentees for Arsenal, and are both unlikely to be recovered any time before late-October.Defender Benjamin Mendy is back and may feature in his first game for City since Manchester City. Raheem Sterling and Kevin de Bruyne have both been passed as fit and will likely feature for the reigning champions, although may potentially not start following their excursions at the World Cup for England and Belgium respectively.Arsenal’s first game of the season as been one to remember for the past two seasons, beating Leicester City 4-3 in 2016 and then losing by the same score to Liverpool last seasonIn the pre-match press conferences, both Spanish managers were full of praise for each other, with Guardiola saying of his counterpart: "He [Emery] is an excellent manager. What he achieved - three Europa Leagues in a row - is excellent. He is a good manager and it is good for the Premier League.”Emery spoke of the stability that Guardiola now has at City after two years at the helm in Manchester, and praised his achievements as a manager, saying “his career as a coach is bigger than me”.City didn’t make many changes over the Summer, with only the one big-name signing in the acquisition of Riyad Mahrez from Leicester City. The Algerian has proven Premier League quality, and has caused Arsenal problems in the past and will be looking to the do the same in his debut for his new club on Sunday.Perhaps the worst part of last season for Arsenal happened immediately after the best part – Arsenal got to the league cup final, where they were comprehensively dismantled by Guardiola’s City. They faced each other once more the very next game, this time in the league – again, a bad beating. Both these losses were followed by a defeat to Brighton, and the atmosphere at the Emirates reached its lowest ebb of the campaign.There’s a lot of positivity around the club at the moment following the much-desired change and a fine pre-season, but things can change quickly in football.With wins for Manchester United, Tottenham and Chelsea in their opening matches, a gauntlet has already been laid, and picking up points and staying in contention with these sides towards the top of the table will be imperative to whether or not this is a campaign to look-back fondly upon.In all honesty, this first match may be too much for an Arsenal team in a huge period of transition to handle. If they can get something out of this game, it would represent a good start to the season.Arsenal play Manchester City in the opening game of their 2018/19 Premier League campaign on Sunday August 12th in the Emirates Stadium with kick-off scheduled for 4pm.