The winger agreed a five-year deal to sign for the Blues in February after a £36.6million fee was agreed with Ajax before the end of last season.
Ziyech was the first of a raft of new signings in west London but he was the last to make his first team debut after picking up a knee injury in pre-season against Brighton.
Ferdinand, a close friend of Lampard, has revealed the Chelsea boss was ‘majorly disappointed’ with Ziyech’s injury as he had raved about the winger’s ability to ‘unlock’ defences in the tightest matches.
Speaking to the FIVE YouTube channel, Ferdinand said: ‘He [Ziyech] was one of the signings that went a bit under the radar because he had an injury.
‘I spoke to Frank [Lampard] just after he signed and he picked up his injury and he was majorly disappointed.
‘He said: “Rio this guy is the guy that can unlock things. If it’s tight in a game he’s the one especially away from home in the big games he can unlock things”.
‘He has the personality, he wants to try things. He can give it away six times on the bounce but he’ll still try that outlandish pass to create an opening. That’s what Frank likes and that’s what the team needed.’
After a difficult start, Lampard has found a winning formula to incorporate his news signings and Ferdinand thinks Ziyech is the pick of the bunch.
‘They’ve [Chelsea] got the man [Ziyech], the person who creates chances, the guy who takes risks, the guy who wants to open teams up at every given opportunity,’ said Ferdinand.
‘Ziyech is just pulling the strings form that right hand side. Two assists at the weekend and he could have had more. Putting the ball on a plate for people to finish.
‘For a forward like Timo [Werner], Tammy [Abraham] and the others they must be looking back and thinking: ‘I’ll make a run and this guy will find me’.
‘Has he got the best left foot in the league? In terms of finding and searching people out. He’s been back a couple of weeks but what he’s done and the impact on this Chelsea team cannot go without being mentioned. Is he the man in form in this league?’