Arsenal midfielder Alex Iwobi hailed their first-half after victory over Chelsea on Saturday night.
Alexis Sanchez, Walcott and Mesut Ozil put the Gunners out of sight before half-time at the Emirates Stadium.
"We've started the season very well, we're mentally up for the game and that's the main thing. As long as we're mentally strong we will do well," Iwobi told arsenal.com .
"We're training very well and we're just putting a lot of training into matches, which is on show today."