Martinelli signs new long-term contract with Arsenal
The Gunners said the 19-year-old Brazilian has agreed a "long-term" deal.
Martinelli has scored 10 goals in 26 appearances in all competitions this season after joining from Brazilian club Ituano last summer.
"I am very happy that Gabi has signed a new contract with us," said head coach Mikel Arteta,
"He is a very talented young player and he has impressed us with his performances, attitude and work-rate."
Martinelli will miss the rest of the 2019-20 season after undergoing surgery on his left knee following an injury in training last month.
"We are looking forward to getting him back to full fitness and to watching his development at our club," added Arteta.
Martinelli is the second Arsenal youngster to sign a new deal this week after Bukayo Saka.