Morata is joint top scorer in the Premier League after finding the net six times in as many matches, which includes a hat-trick in the 4-0 win over Stoke on Saturday.
He said: “I am happy with my start in the Premier League but I can do better.
“I had two chances at the end of the game against Stoke (but didn’t take them). I also need to improve my physical condition to be as good as possible.”
Morata added: “It’s a very important week before the international break and we need to give our best for these two matches. We have a Champions League match now and we have to keep working.”