We saw a surprise in the EFL Cup semi-final match and it was very interesting and exciting. Arsenal lost the match and they are very likely to be eliminated from the semi-finals. Newcastle played strongly and with excitement which resulted in them achieving a good result to qualify for the final. Newcastle are two goals ahead in the first leg of the semi-final, of course they will be even stronger against Arsenal in the second leg to qualify for the final. I think Arsenal may not be able to score as many goals in the second leg so their chances of going to the final are also very low.
I wasn't surprised to see Newcastle United winning, this is due to lack of quality players that are absent in Arsenal's squad, every team found it difficult when few of their first eleven players are absent, it will affect the team to bring out best in them. Newcastle are in good form that's why I have confidence in their victory since arsenal players like Takehiro Tomiyasu, Raheem Sterling, Ben White and Bukayo Saka are injured. Their absence will definitely be a disaster for Arsenal and I don't see them bouncing back in Newcastle's home since they have conceded two goals at home. Newcastle will not like to give a chance after many years of winning trophies and I strongly believe in their current performance that if the still push harder it will be for them.
All this people you mentioned can still be in the game and Newcastle can actually win, if you check at their last Head to Head in their last 5 games, it has been 2 wins for Arsenal and 2 wins for Newcastle and 1 draw. So looking at it Newcastle is not that team that you could easily say if all the Arsenal players where complete for Arsenal they would have gotten win or played better, at best what I saw in that game would have been a draw if the entire Arsenal team where complete. Newcastle are currently on fire and they are one team that can easily score you double goals in a twinkle of an eye, unfortunately for Arsenal they were one of the victims of Such in last night game.