The booming singing voice declaring love for Mesut Özil at the far side of Arsenal's indoor training area could only belong to Lukas Podolski. Özil walks calmly by, seemingly doing his best to ignore this one man serenading act.

During the dip that the club's record signing endured midway through his maiden season in England – something that both his experienced German team-mates regard as totally normal – his compatriots played a key role in supporting Özil. From Podolski, Arsenal's resident joker-in-chief, there was levity and laughs. From Per Mertesacker, the de facto big brother of this gang, came conversation, understanding and a great protective arm around the shoulder.

Even merely talking about the list of surprises he has faced in his first year, Özil makes it sound overwhelming. "We had many matches. The pace was massive. The matches were exhausting. Always forward and backwards. Even against the smaller clubs. Even if it was 3-0," he says. "In Spain the opponents stopped fighting when it was 2-0. It was the first time that I didn't have a break in the winter. It was the first time that I had a muscle injury." Having friends around him for guidance was invaluable.

Mertesacker and Özil go way back. They were team-mates for club and country before, in Germany with Werder Bremen. Mertesacker remembers a 20-year-old Özil scoring the match winner in the DFB Pokal – the German Cup – in 2009. He caught the eye with a sudden sprint, one soft touch controlled the ball and, with a fierce lash, he whipped it in at the near post. As Bremen celebrated winning the cup he looked a picture of youthful, prodigious talent, without a care in the world.

Mertesacker is quietly hopeful that Özil is set to shine in another cup final, on the Wembley stage this weekend. There has been a lot to take in during this campaign and Mertesacker observes that Arsenal's marquee signing looks ready to graduate from the adaptation period and backs him to feel completely at home for the start of next season. Wembley would make a perfect graduation ceremony. Özil certainly sounds in the mood for it. "We want to take this silverware now," he says. "I am convinced we will achieve that. We can win titles with this squad. This is very important for the fans as well. They have been waiting for so long. But it will be a tough game. Hull will fight until the end. Nowhere else except in England are there so many teams who never give up."

Özil's form is rising. His English is improving. Naturally Mertesacker and Podolski were there to help along the way – especially after the nadir of this season when Özil felt the heavy responsibility of a squandered penalty against Bayern Munich in the Champions League and retreated into himself. His compatriots stepped in to guide him back. "We tried to talk to him every day," says Mertesacker. "I think it is very important to keep his confidence high because, when you go through that moment, you suffer a bit and you feel low, we've got a good squad to encourage, especially the Germans, of course. I knew he would suffer at some moment in his first Premier League season, so we are happy that he is fit again and that he has got a few games under his belt to go now to Wembley and show everything."

Mertesacker's role at Arsenal has evolved since his own challenging first season. He is valued as a leader and organiser and the spirit with which he plays has struck such a chord with the supporters they bestowed on him a cult hero nickname. Putting it politely, it rhymes with "Big Bucking German" and at first he was alarmed. "I was frightened at the start because of the 'F' word," he says. "It was always a bit weird. A German journalist told me: 'They quite like you.' My first impression on that was not good but finally I got it." Now he likes it so much he has his own BFG range of T-shirts.

He is intrigued by the notion that he, rather than a more creative player, gets such adulation. "That is a hard question," he says. "But I think the fans like when you play in your way, in your honest way. I'm not going to do anything stupid. It is not only the skilful players who can make the difference in a game. It is as well players who just try to stick to their qualities and give absolutely everything."

That resonated in the FA Cup semi-final, when a rare Mertesacker mistake gave Wigan Athletic a penalty. They found themselves chasing the game and it was Mertesacker who provided redemption with the equaliser. That experience sticks with him before the final against Hull City. "I think we are aware, if something happens, we will not collapse," he says pointedly.

He describes the mood in the camp as "excited and a bit nervous", which he reckons creates the right blend to keep everybody confident and focused. He knows how much it would mean to Arsenal to have a trophy as some kind of concrete confirmation that they can be successful. "That would be a big step for our team," he says. "We went through a lot of difficulties. We were top of the league, then we dropped points and then came back to fourth position. We won five consecutive games. We want to continue with that on Saturday."

Özil, whose former club Real Madrid are preparing for the Champions League final, seems happy enough with his lot provided there is a happy ending. "I am very proud of the team," he says. "We qualified for the Champions League and if we win the FA Cup, it will be a great season."

Mertesacker feels the club is in a different place from the situation he joined as part of a panic spree in the summer of 2011. "There were a few years where we lost quite a few key players every single season. I think eight players have extended their contracts and the manager is likely to do that as well, so the core is together and that has changed the belief, the togetherness, the confidence. We think we can achieve something with this group. We are in a much stronger position than when I came."

They might well feel that way. Now it is up to the players to provide some tangible proof.