When Kieran Tierney arrived in a £25m deal from Scottish giants Celtic last summer, Arsenal may have been licking their lips at thinking they had sorted out their left-back position for the next decade or so. After all, the Scotland international is still only 22-years-old.

But the former Hoops ace has seen his debut campaign in English football blighted by injuries. As per Transfermarkt, a shoulder injury alone has seen him miss 20 games in total, and thus feature just 11 times for the first-team. Hardly the ideal start to life in north London.

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But as is always the case, when one door closes, another one opens. And for Arsenal, Tierney's time spent on the side-lines has seen Bukayo Saka come striding through to stake his claim. The Gunners academy product really broke through under Unai Emery, making 15 appearances for the Spaniard.

And whilst Emery may no longer be at the Emirates, Saka has continued to shine. With both Tierney and Sead Kolasinac out with injuries, the 18-year-old has had to deputise at left-back. And against Bournemouth in the FA Cup fourth round on Monday night, he really laid down a marker.

As per Sofascore, his 8.4 match rating was the highest of any player on the pitch, and when looking at his underlying numbers, it is easy to see why. Aside from his impressive goal and assist, Saka had 73 touches, attempted five crosses, provided two key passes and won three ground duels too.

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He was a constant threat with Gabriel Martinelli down the left-hand side, often overlapping the Brazilian to then fire in low crosses into Eddie Nketiah. But for some last-ditch defending from Bournemouth, Saka could well have picked up a couple more assists such was his excellent attacking work.

If Arteta is intent on playing front-foot football, then having someone like Saka at full-back could be vital. Being the natural winger that he is, he is inclined to be more comfortable with his work going forward, and his thumping effort to score the opener proved that to be the case.

So whilst Tierney may have cost big-money in the summer, Saka's impressive display in the position raises a major question about whether the Scot will be the Gunners' first-choice left-back for the years to come.

Meanwhile, this Arsenal starlet has been tipped to follow in the footsteps of Ronaldo.