Despite only accruing four points from five matches, Walcott believes the Gunners will soon turn the corner and can go on a winning run.
"We've just got to forget about (last week)," he told Absolute Radio's Rock 'n' Roll Football.
"We're scoring goals. We managed to score three goals away from home and still lost, which was disappointing.
"But we just need to forget about it. We need to just move on.
"That is important for us, not to dwell on these results we've had.
"We just need to try and just win, take it game by game. Maybe we're thinking too far ahead at the moment.
"As soon as we start getting a good run, hopefully you'll see the true Arsenal come back.
"Manchester United had a bad start last season, not as bad as us, but you can bounce back from that so we've got nothing to worry about."