The Blues pair will form a formidable partnership in time at Stamford Bridge, according to the Brazilian.
Hazard and Morata linked up well last night in the 3-3 draw with Roma in the Champions League.
The Blues had the Belgian to thank for rescuing a point with a 75th minute equaliser.
“They are great players and have great quality,” Willian told the Evening Standard.
“But they can improve more.”
Antonio Conte’s side squandered a 2-0 lead at Stamford Bridge with David Luiz and Hazard on target.
Former Manchester City players Aleksandar Kolarov and Edin Dzeko tuned the match around for Roma though as they left 3-2.
That’s before Hazard netted the crucial equaliser.
The result did no damage to Chelsea though as Atletico Madrid were held to a 0-0 draw by minnows Qarabag.
That leaves the Blues top of Group C, two points clear of Roma.
After last night’s match Hazard gave his own assessment of the performance.
“I think for the fans it was a good game to watch but for Chelsea, it was like 50 per cent because when you are winning 2-0 at home, you must win the game,” he said.
“But Roma have good players and they created a lot of chances and a least we take one point and it is not a bad result.
“We stay first in the group and we will go to Rome to win the game because we want to finish the job early.”
Chelsea return to Premier League action on Saturday when they host Watford.
