LONDON — Newcastle took a giant stride toward the League Cup final, as goals from Alexander Isak and Anthony Gordon earned their side a 2-0 semifinal first-leg win at Arsenal on Tuesday.

The Magpies, who have not won a major trophy since 1955, will now be clear favorite to complete the job in the second leg on Tyneside next month.

In Isak, Newcastle has the form striker in England right now, and he rifled home the opener before helping tee up the second for Gordon.

Arsenal has a mountain to climb when the sides meet for the second leg on Feb 5 if it is to progress to meet either Tottenham or Liverpool in the final.

"It's massive. It's a great result, but it's only the first half," said Isak after Newcastle's seventh consecutive win, and its first at the Emirates since 2010.

"If we don't go through, then this has no meaning."

The importance of silverware to both clubs was reflected in the lineups, as Mikel Arteta and Eddie Howe named their strongest available teams.

Arteta has brought Arsenal back into contention for Premier League titles in recent seasons, but his only trophy in charge of the Gunners came five years ago, when his side lifted the FA Cup in the early months of his reign.

The host was able to welcome back Kai Havertz, Martin Odegaard and Gabriel Martinelli from the side that started Saturday's 1-1 draw at Brighton.

But, Arsenal's lack of a lethal striker like Isak proved the difference between the sides.

Arsenal had the majority of the ball and the chances, but failed to make them count.

"That was the biggest difference in the game. In every other aspect, we were the better team," said Arteta on his side's wasted chances.

"I have full belief. I have seen my team playing against them. I believe we can do it!"

Martinelli came closest when he raced onto Leandro Trossard's pass and smashed the ball against the post.

The sucker punch came moments later. Arsenal, so renowned for its own set-piece threat, allowed a long freekick into its box to fall at the feet of Isak, who fired the ball in off the underside of the bar.

The Swede's 14th goal in his last 15 games took him to 50 in a Newcastle shirt — achieving the milestone in five fewer matches than the club's record goalscorer Alan Shearer.