After four encounters already this season, nothing could split Arsenal and their west London neighbours Chelsea.

4 games, 4 draws - it seemed destined that Wednesday night's game was going to be the same... but that wasn't to be the case, and the Gunners are going back to Wembley!

In an all-to-play for semi-final second leg, things started quickly with Eden Hazard putting the Blues in-front after seven minutes, but shortly after was Chelsea centre-back Antonio Rudiger's first mistake of the night, and Arsenal's first goal.

His second error came in the game's second half, and Granit Xhaka's finish as a result of it sets up a League Cup Final against Pep Guardiola's Manchester City on the 25th of February.

The final will represent Arsenal and Arsene Wenger's tenth appearance at Wembley in just the last four seasons - with Arsenal winning on all of the past occasions. If Arsenal are to continue this record, it will mean that they have won their 4th trophy in 5 years and that Wenger will get his hands on the only domestic trophy that has evaded him during his 21 years with the club.

Sitting behind the bench on the night was new signing Henrikh Mkhitaryan - unable to feature in any capacity due to being cup-tied - and he will have been heartened to have seen a strong and dominant performance that showed both tactical awareness and attacking threat.

In the first game since Alexis Sanchez's departure from the club to join Manchester United was officially confirmed, Arsenal did not look like a side that particularly missed him.

Perhaps they have got used to the Chilean not being in the team with the furore surrounding his future; perhaps it's the lift given to the side after a reportedly divisive figure departs; or perhaps, speaking pessimistically, his loss will be noticed more in the coming weeks - regardless, the performance was good on Wednesday night at the Emirates.

It was Wenger who summed the situation as it stands up best in his post match press conference: "We lost a great player in Alexis Sanchez but when a team doesn't know what's going on in the dressing room there is less clarity and focus on performances. We know we have to deal with it now."

This Semi-Final performance was a tactical triumph from the Arsenal manager and his players. Arsenal began the game with a 4-3-3 formation, but, following a ropey start, opted to change to a system with wing-backs and Mohamed Elneny seving as a defensive midfielder in-front of centre backs Nacho Monrel, Shkrodan Mustafi and Laurent Koscielny.

Further up the pitch with this new formation, Wenger's more advanced midfielders shifted between positions, with Mesut Ozil having the freedom to play an open role, which worked very well. Following the game, it was clear the players on the field noted the positional errors at the start of the match with Jack Wilshire admitting that "we might have got the formation wrong in the first 25 minutes".

It did not take long for this match to surpass the previous leg in terms of entertainment value. Straight from the off, both sides went at it with hammer and tongs, with Chelsea appearing superior.

Home fans were left fearing the worst after only seven minutes when Tiemoue Bakayoko played the ball into Pedro and he released the ever-threatening Eden Hazard, who slotted past David Ospina from 12 yards out.

Thankfully for the Gunners, it did not take long to respond, thanks in-part to a stroke of luck. Five minutes later, following a kerfuffle in the box, a Monreal header bounced off the unfortunate Rudiger and ended up in the Chelsea net. 1-1.

It was Rudiger who was left with blushes again in the run-up to the decisive second Arsenal goal, when Alexandre Lacazette's early second half pull-back in the Chelsea penalty are rebounded off the German international and into the path of Xhaka who made no mistake.

From this advantageous position, Arsenal could have sat back, but instead they opted to go for more, encouragingly. Alex Iwobi might have made the closing stages more comfortable for Arsenal had he finished from Özil’s cross on 76 minutes but Wenger’s team had done enough.

Along with the formational changes, one of the moments that Chelsea gaffer Conte defined as "decisive" came after half an hour when Willian felt his hamstring and needed to leave the field. On came new signing Ross Barkley, who I think it is fair to say has not yet assimilated himself into the Chelsea system just yet, especially considering it was the Englishman's first game of the season.

Conte suggested that Willian's injury wasn't that serious following the game, and suggested that injuries like this occur as a result of a packed fixture schedule - something his Arsenal counterpart can relate to in abundance.

The Gunners now have close to a week’s rest - which has been rare in recent times - as they will not be featuring in the FA Cup 4th Round matches at the weekend. That means the next match comes up against Swansea City at the liberty Stadium in the Premier League on Tuesday the 30th of January.

One factor that offers encouragement against Guardiola's City side in the final is that they are not unstoppable - Liverpool proved that when they defeated them in the League last week, and Bristol City scored 3 goals against them across the two semi-final legs.

With League matches and both of the Europa League Round of 32 ties against Ostersund to come before the final against City, the game will have to go to the back of Arsenal player's minds for the moment. Hopefully there will be some more squad additions and clearing up of injuries in the interim, as it will not be easily earned silverware.