The current Arsenal boss is coming under increasing pressure at The Emirates following their disappointing start to the Premier League season.
Arsenal lost 2-0 to top-four rivals Leicester City at the King Power Stadium on Saturday evening after goals from Jamie Vardy and James Maddison.
The Gunners are in sixth position and eight points adrift of fourth-placed Manchester City following their third Premier League defeat of the season.
Arsenal have only managed to win one of their last six top-flight outings to see the Gunners lose significant ground on their top-four rivals.
Emery has been contending with speculation surrounding his future over the past couple of weeks.
However, former Arsenal captain Vieira believes the Gunners need to stuck with the Spanish head coach despite their difficult run of results.
“It’s true Arsenal are going through a tough spell,” Vieira is quoted as saying by Metro. “But I haven’t watched all their matches, so I can’t talk about their game.
“They have a coach who is qualified and who works well. When a club is having a difficult time, it’s important to be united.
“I think he has enough experience to get them through this difficult spell. We have to get behind him and give him time to change things. I am not sure a change of manager will fix the problems.”
Arsenal appointed Emery as Arsene Wenger’s replacement in May 2018.
Emery led Arsenal to a fifth-placed finish and the Europa League final in his first season in charge.
The Gunners signed six new players in the summer transfer window to bolster Emery’s squad, including club-record signing Nicolas Pepe.
However, the £72m addition has struggled to live up to his price tag so far.
MORE: Man United latest news
MORE: Arsenal latest news
MORE: Chelsea latest news
MORE: Liverpool latest news