The Hammers were thoroughly outplayed at London Stadium, with Erling Haaland scoring both goals for City.
"We need to freshen up a little bit, we're a bit stale at the moment," Moyes told Sky Sports.
"But look our centre-back [£28million signing Nayef Aguerd] gets injured in a pre-season friendly and we can't do anything about that. So we have attempted to do it.
"Our centre-forward is getting himself fit. The goalkeeper we signed [Alphonse Areola] plays today after Lukasz [Fabianski] gets injured
"You can see we've still got a bit of work to do."