Since signing from Real Madrid in a deal that could reportedly cost as much as £70 million, Morata has scored eight goals and supplied three assists in 15 appearances in all competitions.
The striker has been partnered up top by Hazard in recent weeks, with head coach Antonio Conte adding an extra body into the centre of midfield.
Lampard, Chelsea's record goalscorer, is excited by the way the two work together and believes there is even more to come from the Belgian in particular.
"For me Eden Hazard is the key player for Chelsea," he told Omnisport, speaking thanks to Chelsea FC club partners Yokohama Tyres.