Mikel Merino is expected to start on the bench in Saturday’s Brighton test [Samuel-Carreno/SPP]

MIKEL Merino finally arrived at Arsenal this week, and as he donned the No 23 jersey, he made a vow that will no doubt excite the supporters.

The midfielder has signed a four-year contract, with the option for a further 12 months, after Arsenal struck a deal with Real Sociedad that will see the Gunners pay an initial £27.4million up front, and a further £4.2m in add-ons.

As seems to be the norm these days, pictures quickly emerged of Merino wearing an Arsenal kit as a young boy. And if that wasn’t enough to win over Gooners, how about the fact that the Spain international won more duels than any other player across Europe’s big five leagues last season?

Fresh from winning the Euros with Spain in the summer, Merino has started his new life in north London by making the fans a promise to “fight for every ball with 100 per cent”.

Insisting that he can’t wait to bring those qualities to his new club, the 28-year-old told Arsenal’s official website: “I think that’s a big part of my game and that shows the character that I have.

“I want to fight for every ball and this is something that I learnt when I was really young.

“Maybe you can win it, or you won’t. I’m not promising I will win every duel, but what I can promise is that I will fight for every ball with 100 per cent.

“It’s always tough to talk about myself in those kinds of terms, but I think I’m a hard worker, I want to call myself a good teammate. I like to work for the team with or without the ball.”

Mikel Arteta is expected to name Merino on the bench on Saturday when Arsenal host Brighton.

But judging by the way the Gunners boss was purring over his new signing, it won’t be long before we see the tough-tackler running the midfield.

“Mikel is a player who will bring us huge quality with his experience and versatility,” said Arteta.

“He has played at the top of the game at both club and international level for a number of seasons now. Mikel will make our squad significantly stronger, with his technical ability, together with his strong and positive character and personality.”

Meanwhile, there could still be plenty of transfer activity at Arsenal before the window officially closes tomorrow (Friday) night at 11pm.

Eddie Nketiah is on the brink of joining Crystal Palace in a deal that will pocket the Gunners an initial £25m, with £5m in performance-related add-ons. With Gabriel Jesus struggling with a groin injury, Arteta has admitted that Arsenal are “a little bit short” in attack, so supporters will be eagerly awaiting to see if the club makes a late move to sign a striker.

Elsewhere, Fabio Vieira has all but completed his loan move back to Porto, while Fulham and West Ham are both rumoured to be interested in signing Reiss Nelson.