The 26-year-old’s £65 million move to Man City from Bournemouth was confirmed on Friday and he went on to make his debut the day after.
Semenyo scored City’s sixth goal and provided the assist for Rico Lewis’ first as the Premier League side routed league one Exeter City.
Speaking to reported after the game, Lewis said: "It's not a surprise for us because everyone has seen how good of a player he is in the Premier League.
"Everybody wanted him, there's a reason for that and he's shown that today. It feels like a seamless transition into the team.
"He's a really good person as well which is another positive."
