“I think he’s done very well, it’s a good start for him. His improvement since leaving Chelsea and playing in Italy has been great,” Lampard told BT Sport.
“He’s got six goals in nine games which is impressive for anyone. His chance conversion rate is down which shows you how much room for improvement there is.
“I think his temperament and his confidence in himself has grown since he was in England before.
“He’s always in good positions, he takes the inside left channel brilliantly. He’s playing very well, scoring goals in all positions.
“He’s a good signing and there’s room for improvement for more," he concluded.