But their results have not improved, which has led to significant criticism of the Spanish coach.
Many believe he is on the verge of losing his job, given the distance between the team and the top four in the Premier League at present.
Upson spoke about Emery's tenure and said to BBC Radio 5 Live: "A loss to Southampton [following the international break leaves [Emery] in real limbo because I think he's struggling.
"I was at Leicester [before the international break] and I saw a really poor performance from Arsenal.
"It was almost like they tried to cater to not get beat at Leicester who were on top form, and this is Arsenal, and never really got any kind of grip of the game."
He also felt Emery may have lost the dressing room.
Upson continued: "Maybe, maybe that's the case, maybe there's already a loss of belief or whatever it may be in the manager.
"Emery came to the club and he tried to change things, he tried to be more disciplined. Again you have to look at the recruitment, don't you?
"To spend what they have spent on an attacking wide player, with the other issues that need to be addressed in the team…
"I thought he had a decent first season. At the end of last season you thought: 'You have to progress next season' but I don't think they have."