Manchester United manager Ruben Amorim has warned Arsenal striker Viktor Gyökeres that he faces a battle to maintain his form now he has moved to the Premier League. Gyökeres was prolific under Amorim at Sporting CP,

Latest Arsenal news as Man United boss Ruben Amorim sends a message to former Sporting CP colleague Viktor Gyokeres ahead of Sunday's game at Old Trafford

Mikel Arteta says it took one phone call to be convinced that Viktor Gyokeres was the right signing for Arsenal. Gyokeres joined the Gunners this summer from Sporting CP in a deal worth £64million and is already up and running for his new club having scored in a pre-season friendly win over Athletic Club.

Gyokeres indeed blossomed after leaving England, enjoying two sensational seasons at Sporting Lisbon, where he netted an astonishing 97 goals in 102 appearances, securing back-to-back Primeira Liga titles and a national cup, while also finishing as the league’s top scorer in both campaigns.