Arsenal manager Mikel Arteta said new signing Gabriel Jesus “creates chaos” after the Brazil forward scored in a 2-0 friendly win over Everton.
The £45m signing continued his impressive pre-season form by firing home from a 33rd-minute corner at the M&T Bank Stadium in Baltimore.
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 in Las Vegas.
Chelsea took the lead in the 55th minute when Timo Werner converted the rebound after his initial effort was blocked by team-mate Michy Batshuayi.
Club America drew level in bizarre fashion as Reece James played a blind backpass that evaded keeper Marcus Bettinelli.
Mason Mount scored a superb winner with seven minutes remaining, shifting the ball away from a defender before curling in from 20 yards.
Chelsea face Charlotte FC in North Carolina on Wednesday before meeting Arsenal on Saturday, while Club America face Premier League champions Manchester City in Houston on Wednesday.