"If Bernd starts, I believe in him also".
"For Saturday, the decision for me is easy".
Cech was involved in a Twitter exchange with Leno's former club Bayer Leverkusen on Monday after nearly scoring against City as he attempted a pass across the face of his own goal.
"Also I think he has experience and he has quality, he has the capacity like a first goalkeeper with us".
Cech was subject to criticism on social media, with Leverkusen's official Twitter accounter saying, "We might know a guy" when posting a 29-second video of Leno playing out from the back.
"I am very happy with his performance", Emery said of Cech.
City are much more talented than Arsenal right now; they are much better organized right now and, for that, we shouldn't put too much weight on the first game of the season.
"We are going to play away but we need to keep our personality, keep our mentality", added Emery.
The Gunners appointed Emery as their new manager following Arsenal's sixth-placed finish under Arsene Wenger at the end of the 2017-18 Premier League campaign. "We are in this process". However, it is not an excuse for some of the things we saw.
Arsenal travel to Stamford Bridge to face Chelsea on Saturday evening, hoping to rebound from a 2-0 loss to Manchester City. "We want to prepare for each match by putting difficulty and demands on the opposition".
Arsenal begin the season with a major issue in defence, as Sead Kolasinac will miss around ten weeks through injury and Nacho Monreal is not back to full fitness after returning from the World Cup with a knee problem.
Ainsley Maitland-Niles started against City but had to be replaced early on by Stephan Lichtsteiner after suffering a leg fracture that will keep him out for at least two months.
However, Lehmann said he was "surprised" that Cech tried to play out from the back so often against City. "The two options we have now are Nacho Monreal and Lichtsteiner to continue in this position", Emery told reporters.