Chelsea hero Mikel John Obi is unsurprised by Frank Lampard's success in management.

The Nigeria midfielder, currently with Trabzonspor, says his former teammate was the hardest working he played with.

Obi replied without hesitation when he was asked to name the hardest working player he has played alongside.

"Frank Lampard," said the 31-year-old, who played alongside the current Chelsea head coach for eight seasons from 2006 to 2014.