Mikel Arteta has challenged Arsenal duo Bukayo Saka and Kieran Tierney to make the left-back spot their own.
Scotland international Tierney was considered a coup when the Gunners landed his signature last summer, spending £25million to bring him south from Celtic.
But Tierney arrived with an injury and has only returned to training this week after being out since December with a dislocated shoulder.
His last appearance came in the 3-1 win over West Ham in early December, but he could feature in a first matchday squad under Arteta when the Hammers visit the Emirates this weekend.
Standing in his way where a starting spot is concerned however is teenager Saka, who, despite preferring to play further forwards, has seized his opportunity and made the left-back position his own.
With Sead Kolasinac also suffering from intermittent injuries and failing to really impress Arteta, Saka emerged as first choice and has started eight of the last 11 Premier League matches in the position.
The 18 year-old already boasts nine assists in 28 first-team outings this term, and has become more diligent defensively, having been working on his positioning on the training ground.
Now Arteta has told the duo that he is ready to let them do battle to be the definitive first choice.
"They [Saka and Tierney] have to compete, they have to challenge each other and improve," declared the Spaniard..
"Whoever is best will be in the position, which is a really good thing for the team."
With regards Tierney's return to fitness, Arteta added: "He's done two or three complete sessions now.
"He's feeling more and more confident with contact around him and hopefully he will join in the [matchday] squad soon."
Such has been Saka's rise, he has been mentioned as a potential call-up to the senior England squad later this month - despite being still to make his Under-21 debut.
He has been the overwhelming success story of a largely underwhelming campaign for the north London side, and while Arteta insists he has no issue with a potential call from Gareth Southgate, he also offered a word of warning.
"I think he [Saka] is doing really well with us," he continued. "[But] international level is a different level.
"It is up to the England manager to discuss whether he is ready to do that and what is he going to do with his squad. Whatever he decides we will support the idea and the player."
