The Blues opened scoring 38 minutes into the game after Knockaert was beaten too easily by Hudson-Odoi and the teenager fizzed in a low cross to the near post, where Giroud arrived to squeeze the ball in from very close range.
Hudson-Odoi rewarded Sarri’s faith on his first Premier League start.
60th minute, Hazard produced a moment of magic to give Chelsea a 2-0 lead.
He drifted in from the left and picked up the ball in a central area just outside the box. He feints to shoot, sending Dunk sliding away, before curling a lovely strike into the far corner.
3 minutes later, Hazard turns provider for Loftus-Cheek as the pair swapped roles in an almost identical move, with the Englishman firing into the top-right corner from the edge of the box to make it 3-0 to the Blues.
At the other end, City secured a 2-0 win over Cardiff City, thanks to goals from De Bruyne and Sane, as they maintain top of the Premier League table.
City with an early lead, 6 minutes into the game as De Bruyne was played into space by Laporte and he did have options in the middle. Etheridge appeared to be looking that way and was caught by surprise as the midfielder angled his attempt towards goal and he duly found the net.
Sane doubled the lead for City just a minute before end of first half. Mahrez turned his man inside and out down the right flank before supplying a cross to the back post. Jesus guided the ball back to an unmarked Sane with his chest. The German struck his effort first time – low and hard towards the bottom corner, leaving Etheridge with no chance.