Watford winger Gerard Deulofeu says Manchester City boss Pep Guardiola can be as tough as any manager in the game.

Deulofeu played for Guardiola at Barcelona.

"He is a genius coach, special, for everything he has achieved.

"His secret is that aggressiveness that nobody sees, only those who are in the changing room day-to-day," he told DAZN.

"There lies his success, and it is not luck."