Arsenal manager Mikel Arteta said new signing Gabriel Jesus "creates chaos" after the Brazil forward scored in a 2-0 friendly win over Everton.
Jesus, who scored twice against Nuremberg this month, helped set up Bukayo Saka for Arsenal's second.
"He creates uncertainty and he's always on your shoulder," said Arteta.
"He's a real threat and this is what we need. He's very versatile, but obviously the way we would like to develop him is in that [number nine] position."
Arsenal face Orlando City and Chelsea in Orlando next week.
Chelsea began their pre-season campaign with a 2-1 win over Mexican side Club America at the Allegiant Stadium in Las Vegas.