A sluggish Chelsea, in their third pre-season game, fell to a goal four minutes from time from Kawasaki’s Leandro Damaio.
Everton are ready to offer £30 million for Zouma, 24, who had an impressive season on loan at Goodison Park last term.
But Chelsea, under a transfer ban, do not want to lose any of their squad.
Lampard said: “Kurt is a very good defender, a very good player, a professional and I want him here, simple as that.
“We are competitive with the centre backs we have, and he had a very good season at Everton. I understand why they want him.
“But he’s a Chelsea player and I want him. I want him to be happy. He’s working really hard and if he competes and plays well, he plays.”
Chelsea created few chances against the J League champions, who are in the middle of their season, but Pedro, Michy Batshuayi and Oliver Giroud went close.
Lampard added: “We want to win, but ten days into pre-season having flown into Japan only three days ago brings up a lot of difficulties for us physically.
“We are competitive with the centre backs we have, and he had a very good season at Everton. I understand why they want him.
“But he’s a Chelsea player and I want him. I want him to be happy. He’s working really hard and if he competes and plays well, he plays.”
Chelsea created few chances against the J League champions, who are in the middle of their season, but Pedro, Michy Batshuayi and Oliver Giroud went close.
Lampard added: “We want to win, but ten days into pre-season having flown into Japan only three days ago brings up a lot of difficulties for us physically.