French forward Hugo Ekitike made his debut for Liverpool, one week after joining from Eintracht Frankfurt for a reported US$92 million.
Wirtz equalised after Yokohama opened the scoring early in the second half, the German slamming home a right-foot shot from inside the box in front of over 65,000 fans.
“I am really happy that I could score my first goal. I hope there are more to come,” said Wirtz, who joined Liverpool from Bayer Leverkusen in a blockbuster deal.
Trey Nyoni and Rio Ngumoha also scored for Liverpool, who announced the sale of Colombian forward Luis Diaz to Bayern Munich on Wednesday.
Liverpool manager Arne Slot said he was happy to see his team come from behind to win but was not pleased with their missed chances.
“It could be with a tough training camp and it could be with the heat circumstances,” said the Dutchman. “But that’s something that we definitely have to improve.”
Goalkeeper Alisson Becker missed the match after travelling home to Brazil “for private reasons”, Liverpool said.
Shortly before kickoff, an emotional tribute was given to Diogo Jota, who passed away this month in a car crash.
Liverpool dominated throughout but Yokohama opened the scoring when Asahi Uenaka pounced in the 55th minute to beat Giorgi Mamardashvili.
Wirtz levelled when he latched onto a Mohamed Salah pass.
Nyoni volleyed home a Jeremie Frimpong cross to put Liverpool in front, before Ngumoha dribbled from the halfway line and fired in a shot from the edge of the box. (AFP)