LONDON -- The signs are getting difficult to ignore for Arsenal. Whether it is the sight of a No. 14 beating defenders at will and scoring the opening goal, or Anthony Gordon actually invoking Thierry Henry's corner flag celebration when doubling Newcastle United's advantage, reminders of the value of an iconic centre-forward were everywhere on Tuesday evening.

On a less abstract level, Arsenal's finishing at Emirates Stadium was awful, their profligacy a major contributing factor to a 2-0 home defeat which leaves Newcastle firm favourites to progress from this two-legged Carabao Cup semifinal.

The fact they were shown how to do it by Alexander Isak, a player they have tracked for a long time and continue to monitor, only brought the point even closer to home. Isak obviously has a long way to go to match Henry's status in the game, but on current form, he might be the best forward in England and arguably beyond.

His 14th goal -- there's that number again -- from his past 15 games owed something to fortune given Jacob Murphy was trying to collect Sven Botman's flick-on but inadvertently found the Sweden international in the box, but Isak's finish high into the net was deadly.

More smart play from the 25-year-old, this time six minutes into the second half, proved decisive. decisive. Isak collected Murphy's pass in the box and got a shot away which David Raya could only parry into Gordon's path.

"I think [he's the best striker in Europe]," Gordon told ITV Sport. "I think everyone is in agreement with that. He's on fire. Even for my goal. I'm just gambling back post."

Arsenal manager Mikel Arteta also agrees.

"He was involved in both goals as well," he says. "Unfortunately, the two times he had the ball in the box and that's what happens when you have real quality up front and they can make the difference, and they're very clinical."

The clamour for Arsenal to gamble in the transfer market on Isak or a forward of his ilk will only grow now, especially as the catalogue of missed chances will linger in the memory.

Just before the half-hour mark -- and after Jurriën Timber has headed over from inside the six-yard box -- Gabriel Martinelli raced through on goal from Leandro Trossard's through-ball. The Brazilian's effort struck the post.

Kai Havertz and Gabriel Magalhães had shots blocked either side of Isak's opener. Perhaps the most astounding miss came at 2-0 when Trossard's right-wing cross was deflected into Havertz's path. Somehow, almost in slow motion, Havertz failed to connect cleanly with the looping ball, shouldering the ball agonisingly wide of Martin Dúbravka's left-hand post.

Newcastle withdrew Isak for the final 25 minutes due to a tight hamstring, shutting the game down through a series of changes that left them playing something approximating a 5-5-0 formation as Arsenal gradually ran out of ideas.

Nevertheless, the Gunners ended the game with an expected goals (xG) total of 3.12. That is the highest figure by a Premier League team in any game this season without scoring.

Scratching the surface only underlines Arsenal's wastefulness. For all their opportunities, from 23 shots, they managed just three on target and only one of those came from open play.

"If you look at what both teams produced and the dominance it is not the result that reflects the story of the game but the reality is they were super efficient with the chances they had and we weren't," said Arteta.

"At this level, in these kind of scenarios you need that to impose yourself and win again."

Pushed on whether the missed chances -- a familiar issue this season -- could become a psychological problem and how his coaching staff could address that, Arteta chose instead to focus on the Puma ball, a departure from the usual Nike offering used in the Premier League.

"Nothing, just try and show them, give them tips of what we can do better," he said.

"I think we kicked a lot of the balls over the bar and it is tricky: this ball flies a lot. We discuss that as well so there are details we can do better. But at the end, that's gone. This is no way back, it is about the next game. That is our world."

The ball did not seem an issue for Isak. He has now scored 50 goals for Newcastle in all competitions and since his debut in August 2022, only Erling Haaland (105) and Mohamed Salah (73) have scored more goals in all competitions among Premier League players.

Newcastle fans will delight in disproving the theory Isak must leave the club to win the trophies.

Speculation of a price tag as high as 150 million will likely dissuade any suitors this month, but the prospect of a Carabao Cup Final -- the second leg at St James' Park takes place two days after the transfer window closes -- is another pull for Isak to stay put.

Since 1987-88, nine teams have now held a two-goal advantage after a semifinal first leg away win, with all eight previous occasions seeing the side progress to the final.

Reflecting on that half-century milestone, Newcastle boss Eddie Howe said: "It is a brilliant return and I think every team needs a good striker."

Shortly after Isak was substituted, Arteta cast a lingering look at the Newcastle dugout. He may well have been thinking the same thing.