Arsenal have it all to do in the second leg of their Carabao Cup semi-final tie against Newcastle United following a 2-0 defeat in the capital on Tuesday evening. Following Saturday's 1-1 draw away at Brighton & Hove Albion, Gunners boss Mikel Arteta made five changes to his team as Jurrien Timber, Myles Lewis-Skelly, Martin Odegaard, Gabriel Martinelli and Kai Havertz all came into the side.

It was Newcastle who had the best chance in the opening exchanges but Joelinton shot high over the crossbar from just inside the box after Alexander Isak had teed him up. Timber also couldn't keep an attempt down on 13 minutes as he headed over from close range from Declan Rice's corner.

Arsenal were inches away from opening the scoring midway inside the first half as Martinelli struck the post after Leandro Trossard had played him clean through with a lovely pass to open up the visitors. The hosts were made to pay for that miss as Isak netted on 37 minutes following a long free-kick into the area from goalkeeper Martin Dubravka.

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Newcastle were to double their lead six minutes after the restart as Anthony Gordon converted at the far post after David Raya could only palm out Isak's attempt into such an inviting area. Arteta's men did have opportunities to reduce the deficit, notably through Havertz on the hour mark, but the visitors managed to hold on to take a crucial advantage into the second leg at St James' Park at the beginning of February.

Here are five things we spotted in the game in north London:

Injury boost

There was a welcome boost for Arsenal heading into the Carabao Cup semi-final tie following Raheem Sterling's return to fitness. Joining on loan from Chelsea just prior to the summer transfer deadline, the winger's move across the capital hasn't exactly gone to plan so far with limited minutes coming his way.

Getting 70 minutes in the tank in the previous round at home to Crystal Palace, Sterling unfortunately couldn't build on his pitch time due to a knee issue sustained in training that sidelined him for four games. At a time when the north London club are having a few injury issues to deal with, Sterling's return to the bench for Tuesday evening's cup tie was certainly a welcome boost as it gave Arteta another option in his squad.

Even though Arsenal were trailing by two goals 51 minutes into the tie, Sterling didn't enter the fray as the boss opted against introducing him. The experienced attacker will be hoping game time comes his way this weekend when Arsenal take on Manchester United in the third round of the FA Cup.

Midfield decision

With a place in the Carabao Cup final up for grabs, Arsenal and Newcastle were not taking any chances at this stage of the competition. Tending to use the EFL Cup as an opportunity to give those on the periphery of the first XI a go in the team, Arsenal fielded an extremely strong XI and their opponents only made the one change from last Saturday's win at Tottenham.

Arteta opted for his first-choice midfield three to take on Eddie Howe's side as Thomas Partey, Rice and Odegaard lined up alongside one another. Seeing Partey start at right-back on a few occasions recently in the absence of Ben White and with other midfielders getting a start during a busy run of games, it was the first time that Arteta's midfield triumvirate had started together since the 2-0 win over Manchester United at the beginning of December.

It was a decision that certainly went down well with Arsenal supporters and one that perhaps had to be made due to the fact they were coming up against a very impressive Newcastle midfield. The Arsenal midfield would only be together for just shy of an hour, however, as Arteta introduced Jorginho in place of Partey with Newcastle two goals to the good and in total control of the cup tie.

Isak wows

Oh how Arsenal could do with Isak in their team right now. Missing that world-class striker to help take the team to the next level and bring the top honours to the Emirates Stadium that Arteta is desperate for, the Newcastle striker demonstrated to everyone why he is rated so highly in the game.

Coming into the cup semi-final bang in form after hitting 13 goals in 14 games, including six goals in his last four outings, the Swede opened the scoring towards the end of the first half with a clinical finish in the box from Jacob Murphy's pass. It wasn't just the striker's finishing that caught the eye, however, as he wowed with his all-round play and duly caused Arsenal a whole host of problems.

Setting Joelinton up in the opening minutes as the midfielder blazed over, he then showed his quality later in the first half down the right flank as he slowed down and then sprinted beyond William Saliba moments before Sandro Tonali blazed over. His eye for pass was also evident with a sublime ball that set Murphy free towards the end of the first half as the visitors looked to take full advantage of the hosts.

Isak was at the heart of Newcastle's second goal of the evening as he utilised the ball well outside the box before finding space in the Arsenal area to link up with Murphy as Gordon converted after the striker's attempt was saved.

Linked with a move to Arsenal going on his Newcastle heroics and just what he brings to the team, Isak has everything Arsenal require up front right now. He's Newcastle's prize asset, though, and a major reason for their two-goal lead going into the second leg.

That Havertz miss

Havertz's miss on the hour mark could prove huge in the context of the Carabao Cup semi-final tie between Arsenal and Newcastle United. Trailing 2-0 courtesy of those goals from Isak and Gordon, Arsenal had a glorious opening to really give the visitors a scare going into the final 30 minutes.

The German international was in such an inviting position six-yards out as a deflected Trossard cross from the right looped perfectly into his path. Havertz ghosted into a gaping hole between Tino Livramento and Dan Burn but his attempted header actually struck his shoulder and trickled wide of the target.

It was one of those chances where it actually looked easier to score. On a day where Isak delivered a masterclass up front for Newcastle, Arsenal fans wished it was the Swede in Havertz's position as it would have been a guaranteed goal given the form he's in right now.

Gordon replicates Arsenal legend

Arsenal fans got to see a familiar celebration at the Emirates Stadium on Tuesday. Much to the disappointment of Gunners supporters, it was Newcastle winger Gordon who performed it in front of the jubilant travelling faithful.

In the perfect place to tap home from point-blank range after Raya could only palm Isak's shot into his path, the ex-Everton man raced over to the corner flag and replicated a rather iconic Thierry Henry celebration. Grabbing the top of the flag with his left hand and placing his right hand on his hip, Gordon stood there taking it all in just as Henry did a number of times down the years for Arsenal and France.

It was not what Arsenal fans wanted to see.