Japan’s curious 2023 AFC Asian Cup campaign was perhaps best epitomised in the way they advanced to the quarterfinals on Wednesday with a 3-1 victory over Bahrain.

At a tournament where they possibly have the most talented squad and are among the leading title contenders, the Samurai Blue just have not fired on all cylinders.

Against Bahrain, they never looked in danger of falling victims to an upset — it also never seemed as though a statement performance was on the cards.

There were glimpses of Japan’s true potential, of course, with some excellent ball movement and penetration shown in the attacking third, and that is always going to be the case given the sheer talent at coach Hajime Moriyasu’s disposal.

After some inconsistent performances in the group stage led to some tinkering, the starting XI Moriyasu fielded on Wednesday were arguably the ones who have impressed most so far in the tournament.

These included seven different faces to the lineup that started in the 4-2 win over Vietnam in their campaign opener, suggesting that Moriyasu is open to rewarding those who perform rather than have a fixed best XI in his mind.

In that game against Vietnam, it was rather surprising that neither Ritsu Doan nor Takefusa Kubo started.

But now they have been given their opportunity, the two Europe-based stars are exerting the influence many were expecting from them.

Both were left with easy finishes to hand the Samurai Blue a 2-0 lead by the 50th-minute mark — Doan pouncing on the rebound after a ferocious effort from Seiya Maikuma had smashed off the post, while Kubo slid a finish past Ebrahim Lutfalla from what would have been a blatant-offside position had the ball not reached him off the foot of a Bahrain defender.

Yet, it was the way they ran at the opposition defence and linked up with their teammates with sharp passes and off-the-ball movement — which led to some intricate and eye-catching offensive routines — that illustrated the threat that Japan can pose at their best.

Then, Japan again had to show they are far from invincible.

For the fourth game in a row at the tournament, goalkeeper Zion Suzuki made a notable error to allow the opponents back into the contest.

His backline should have done better than to leave Sayed Baqer unmarked at a corner but, with the Bahrain centre-back’s firm header directed straight at him, Suzuki somehow parried the ball into the sky and looping back towards his own goal.

In a desperate attempt to prevent the ball from creeping in under the crossbar, Suzuki raced backwards but failed to realized that Ayase Ueda was on the line looking to bail his custodian out — and could only succeed in pushing the ball of his teammate’s head and into the back of the net after a coming-together that would have been comical to anyone except those in the Japan camp.

Suzuki is a promising talent that only recently earned a move to Europe. He is hardly to be blamed solely for Japan’s unconvincing showing at the back — but it is also impossible to ignore the fact he has now made mistakes in every outing at the Asian Cup.

It is also not his fault that he is one of three extremely inexperienced goalkeepers that Moriyasu curiously opted to select for the tournament, and the Samurai Blue coach has thus far opted to keep his faith in the Sint-Truiden man.

Part of this must to be down to ensuring Suzuki’s confidence is not completely shattered but a case can also be made that the 21-year-old could also do with some protection from the increasing negative scrutiny — lest his entire future is ruined off the back of a solitary disastrous showing at a major international tournament.

For Ueda, he at least had a chance to redeem himself shortly after with a fine individual effort that put the result beyond doubt – taking three opponents in close attention completely out of the equation with a drop of the shoulder before charging towards goal and finishing through Lutfalla’s legs from an acute angle.

Along with Doan and Kubo, Ueda — now on 11 goals from 23 caps — is growing in influence for Japan with each passing game.

Then, there is a certain Kaoru Mitoma.

Having missed the three previous matches through injury, Mitoma made his long-awaited bow at the tournament in the 68th minute.

In just a 20-minute cameo, the Brighton man showed why he is now one of the Premier League’s most-exciting attackers and how he could be the one to turn it up a notch for the Samurai Blue.

Mitoma glided past Bahrain defenders at will either through his speed or guile and it did not even look like he was trying.

His introduction saw Japan create a whole host of chances to win by a bigger margin only for them to be let down by some woeful indecision in the opposition area, with Mitoma — on occasion — as guilty a culprit as others such as Takuma Asano and Takumi Minamino.

Once again, another example of how Japan can look completely ordinary just moments before or after resembling future five-time Asian Cup champions.

Still, the talent is there and it is undeniable, and it will only get more fearsome once Mitoma is fully back up to speed and back in the starting XI.

An attacking midfield trio of him, Kubo and Doan wreaking havoc just behind the focal point that is Ueda will pose plenty of problems to any opposition.

And perhaps for those who prefer to see the glass as half full, the fact that things have not quite clicked fully for the Samurai Blue means that they can only get more formidable going onto the quarterfinals.