Rob Holding says Arsenal teammate Gabriel Martinelli is a nightmare to play against.

The 18-year-old, signed from Ituano over the summer, has scored braces in both of his two starts this season.

"Martinelli has come in and settled really well," Holding told a press conference.

"In training every day, he works hard. He puts you under pressure constantly and never stops running, which as a centre-half is a nightmare.

"You want a striker that will sort of give up on you, but he never gives up. His finishing has been unbelievable, even with his head.

"He's only a small guy but the headed goals he's scored in the Forest game and the Standard Liege game have been incredible goals, to be fair to him."