What went wrong for Unai Emery at Arsenal?

#2 Baffling team selections and substitutions

Unai Emery has been tinkering with different formations and line ups from the start of the season. The Spaniard used five different formations in the 14 league games he oversaw

Unai Emery's fluctuating tactics and formations drove two major conclusions. Firstly, that he did not know his best XI, and that he ran out of depth. Emery did not seem to have trusted a specific formation for more than 3 games in a row and also kept changing the personnel, which led to more doubts amongst players and the board about Emery's ability to turn the season around.

Going by the most recent example of how Unai Emery managed to put the whole fan base into meltdown with one decision, is when he decided to bring on Lucas Torreira for Mustafi against Eintracht Frankfurt, in a game where Arsenal needed goals. He also took Mesut Ozil off for Gabriel Martinelli, leaving Nicolas Pepe and Alexandre Lacazette on the bench, and eventually losing the game.

In the game against Wolverhampton Wanderers at the Emirates, Arsenal were level at 1-1 agains Wolves and the players needed a bit of spark from the bench to get a winner with a couple of minutes left. Unai Emery, judging the situation, brings on Sead Kolasinac for Kieran Tierney in what was his last substitute for the game, leaving Nicolas Pepe on the bench for the whole of 90 minutes. That pretty much summed up how Arsenal were going backwards under Emery.

Arsene Wenger was someone who never changed his style and stuck to his philosphy despite getting poor results in his later years, whereas Unai Emery kept tinkering with formations despite getting good results and made life difficult for the players. A manager clearly needs to balance out on this aspect to achieve short term as well as long term success.