Arsenal great Sol Campbell was amazed by Chelsea striker Romelu Lukaku's goalscoring performance on Sunday.
Lukaku struck on his second debut in Chelsea's 2-0 win at Arsenal.
Campbell, despite his Arsenal ties, couldn't help but lavish praise on their rivals' new front-man.
"He's learned a hell of a lot from Italy," the former Gunners centre-back said on Sky Sports punditry duty.
"(Antonio) Conte has got him up to speed and he's acknowledged that. He's talking to Thierry (Henry) as well, Drogba.
"He wants to learn and continue learning and that's fantastic to hear. Today he was unplayable, incredible."