The Ghanaian played the full 90 minutes at the Etihad Stadium as AFC Bournemouth were beaten 3-1.
An Omar Marmoush stunner followed by a Bernardo Silva goal gave City a 2-0 lead at halftime, before Nico scored a third in the final minute of the 90.
Daniel Jebbison netted a stoppage time consolation but it was a comfortable victory for the hosts.
Reflecting on the game, Semenyo told the Daily Echo: “You can see in the change room everyone’s pretty frustrated.
“Just one of those games, a couple goals you can't do much about.
“But, yeah, just have to keep our heads up. It's been a good season and just try and finish strong.”
_(Image: Richard Crease)_ It was an intense first half, as City gained control of the match.
On the start to the game, Semenyo said: “When you play against a City team like this, you know that you're going to be running around a lot. They started off the first half really well.
“I feel like in the second half we started to pick up momentum, but yeah, just one of those games.”
Despite coming back into the game in the second half, Semenyo admitted it was tricky to break their hosts down.
They started to build some momentum after Mateo Kovacic was sent off, but Lewis Cook saw red six minutes later to check that.
But they did get a breakthrough in stoppage time through Jebbison, the striker reading a poor pass from Matheus Nunes and finishing past Ederson.
_(Image: Adam Davy/PA Wire)_ Semenyo was pleased for his teammate, that goal his first for the club in the Premier League.
“He's been working hard all season round,” Semenyo said.
“He's done well in training and he’s one for the future, so good for him to get on the scoresheet.”
After the defeat in Manchester, the Cherries now cannot qualify for Europe.
Even though the chances were slim headed into the final week, Semenyo said: “There was always a slight possibility, and we had an open mind.
“We knew that we had to come and win today, so, I mean, the journey's over, but I mean, like I said, it's been a really good season.
“I feel that everyone can be proud of themselves and last game, three points.
“Hopefully that's what we can do.”
The Cherries host Leicester on Sunday and Semenyo said: “I think we want to finish off strong, but with the season that we've had this year, everyone can be proud of themselves.
“So get three points in their last game and then just recoup for next season.”