It took longer than anticipated when putting pen to paper on signing for the Gunners, but Mikel Merino is delighted he finally made his debut for his new club. 

While Mikel Arteta's side deservedly earned plaudits for their composed 2-0 victory over PSG at the Emirates on Tuesday evening, another pleasing aspect was the 28-year-old's bow in red and white. 

Espeically when considering the former Real Sociedad midfielder was injured during his first training session after arriving from the Basque country at the end of August. 

Speaking after beating the Parisians in North London, Merino reflected on his injury and what he has learned since, saying: “It was really tough mentally. To come in here, you want to have a nice few days to show everybody what you are capable of, to show why they have put faith in you and then the first thing that happens is you break your scapula.

"But everybody in the club was really nice to me, really lovely, and finally I can say I am officially an Arsenal player now. I have made my debut and I am buzzing.”

Goals from Kai Havertz and Leandro Trossard sealed the Gunners first Champions League victory of their fledgling campaign, following on from their creditable 0-0 draw at Atalanta two weeks ago. 

Such excellent form has been underlined by Arsenal's sprightly start in the Premier League, having won away at Aston Villa and Spurs, as well as the 2-2 draw at Manchester City, which laid down a marker as to the level Arteta's side have now attained. 

Revealing the intensity of training sessions, Merino explained: “I don’t want to tell everything that we do but there is no rest between one moment and the other. They are always challenging you mentally with different stimuluses. It makes you all the time aware of what is happening around you.”

“It’s something that is amazing” he said.

“They do some things that I have never seen in my career. The methods they use are completely new to me so it takes some time to adapt. But at the same time, when you get it you are in a different level because they challenge you every single day – not only physically but mentally. It makes you be sharp mentally and that’s what you are going to find out in the game."

With Arsenal set to host struggling Southampton on Saturday, prior to taking stock with another international break foistered upon the domestic game, Merino has time to adapt still further. 

“I want to grow, I want to learn even more,” Merino explained, adding: “When I spoke to Mikel and I saw what was the plan, not only with me but the whole team, what was the culture. I felt this was the right place to take the next step in my career.

“The mentality they have here is amazing, not only on the pitch but at the training ground – how they focus on the single things, the details, the basics.

"Winning trophies is the main thing for everybody.

"They are obsessed with that.”