Marcos Alonso scored the winner for Chelsea on Saturday as Maurizio Sarri's side beat Arsenal 3-2 in a thrilling game at Stamford Bridge.
Pedro fired the hosts in front after just nine minutes, as he stroked home Alonso's cross. A second followed as Alvaro Morata latched onto a long ball, cut inside Shkodran Mustafi and stroked past Petr Cech.
Henrikh Mkhitaryan halved the deficit with a well-hit low shot that crept inside the post. He then crossed for Alex Iwobi to level the score four minutes before half-time.
The second half was a tighter affair, but Alonso pounced with nine minutes remaining to leave Arsenal without a Premier League point after two games.