Ziyech was the standout player on an emphatic night for Chelsea in the Champions League.
It was the first time he’d been named in a starting XI by Lampard after missing the opening weeks of the campaign with a knee injury.
But Chelsea’s manager believes the former Ajax star has served notice of his qualities.
Lampard said: “I thought his performance was very, very good when you consider he hasn’t started a match since March when the Dutch league finished.
“So I’ve been very excited to get him on the pitch. It’s been frustrating for me and for him, for us that his injury has meant he hasn’t been able to start.
“But from what I’ve seen in training so far – what I knew we were signing is a player of immense quality and personality to receive the ball, find assists, find goals and we saw a lot of glimpses of that and he will get better.
“We brought him in to do a job. Maybe people have forgotten a bit because we signed him in January and he’s missed the start of the season. Tonight he certainly showed that he’s here.”
Ziyech scored Chelsea’s third of the night after Callum Hudson-Odoi and Timo Werner had opened up a 2-0 lead.
Substitute Christian Pulisic rounded off the scoring in the 90th minute.