Manchester City beat Premier League rivals Manchester United, Liverpool, Spurs and Chelsea to Semenyo’s signature.
Speaking at Friday’s news conference, Guardiola confirmed Semenyo will be in the squad for Saturday’s FA Cup third round tie against Exeter at Etihad Stadium.
“He was extraordinary at Bournemouth, he can play on both sides, he knows the Premier League and many clubs wanted him and he decided to join us,” Guardiola said.
“We followed him for a long time. He is the perfect age, 25 or 26 years old, so the best years are to come.”
Semenyo scored four goals in his last six games for the Cherries, putting him third in this season’s Premier League goalscoring charts with 10 from 20 games – behind new City team-mate Erling Haaland (20) and Brentford’s Igor Thiago (16).
He needs just one more league goal to equal his previous best for a season, having scored 11 in 36 Premier League starts last term.
“Antoine is a really exciting signing for the football club. He made it clear to us immediately that it was City he wanted to join,” director of football Hugo Viana said.
“He has huge quality. Two great feet, pace, power, a habit of influencing games and, importantly, real room for growth and development.
“We are constantly watching players all over the world. Antoine was the one we most wanted. He has shown he can perform in the Premier League. He is humble, hard-working, professional and totally focused on being a better footballer. He is ideal for us.”
Bournemouth signed Semenyo from Bristol City for about £10m in January 2023 and he leaves the Cherries after with 32 goals and 13 assists from 110 appearances in all competitions.
Semenyo started his career in the Championship, claiming 21 goals and 21 assists in 125 games for the Robins, having had loan spells with Sunderland, Newport County and non-league side Bath City.
After joining Bournemouth on a four-and-a-half-year deal, Semenyo signed a contract extension last summer – which had been due to end in 2030.