José Mourinho might have struck a chord with Arsenal supporters, as he looked ahead to Chelsea's visit to the Emirates on Monday night and considered how best to shape a squad to win the Premier League title. "If you are just building, building, building … probably, you will never get there," the Chelsea manager said.

The development of players, Mourinho continued, would always be key but there comes the time when a club has to write a cheque to "complete the puzzle", he suggested. Arsenal did so in the summer. Their fans had shouted themselves hoarse demanding a superstar signing but they could revel in the eventual capture of Mesut Özil for £42.5m from Real Madrid.

Mourinho loves Özil. He worked with him at Real over the previous three seasons and he was fulsome in his praise of the attacking midfielder. With Özil, he indicated, Arsenal had found the missing ingredient. They were now complete; capable of staying the championship course.

He could be forgiven for feeling envious. He had identified his final piece in Wayne Rooney but Chelsea could not get the striker out of Manchester United. As a result, and as Mourinho has said on many occasions, his club must contend with something of a transitional season.

"Next season, Chelsea will have a phenomenal team," Mourinho said. "Between the work we are doing [on] the evolution of the players and a couple of clinical signings [next summer] … When you buy two clinical players to complete the puzzle you are building, I think that Chelsea next season will have a really very good team."

Perhaps one of them could yet be Rooney. But Mourinho must wait, temper his natural impatience and deal with the scenario that he painted which, essentially, involved role reversal. According to him, Arsenal were no longer talking of fulfilling their potential; their time had arrived. Chelsea, by contrast, were caught between their younger players who would improve and the older ones that could no longer perform in every minute of every game.

"I think, in the deep of their souls, they [Arsenal] think they can [win the title], they believe they have the conditions to do it," Mourinho said. "In my previous time here, Walcott was a kid. He's now a man. Other players are in the best moment of their careers – Wilshere, Ramsey and Gibbs.

"I'm not saying Mesut transformed the team completely. The manager and the club has given players conditions and time to have great stability in their evolution. And now, when you buy Giroud and now Özil and some other players, the team becomes much better and ready to be doing what they are doing which is to fight for the title."

It is difficult to see Chelsea as the underdog, and not only because they spent rather more than Arsenal in the summer – around £58m on players who included Willian, André Schürrle, Samuel Eto'o and Marco van Ginkel. Mourinho has never lost to Wenger in nine previous meetings and there were flashes of that famous self-belief. "We can, we can," Mourinho replied, when asked whether Chelsea could send a message by toppling Arsenal.

Mourinho believes that the title race ought to have been shaped decisively. "In normal conditions, Manchester City should be far from the others because the squad, the maturity, the stability of the players, the potential of the striking force, the experience of the players …" Mourinho said, pretending to wave goodbye. "There is a difference. But the Premier League is being difficult for everybody, also for them. So, in this moment, everybody is there. So, I think: good fun."

Özil has been good fun, although he has shown signs of fatigue from the relentless demands of English football. "It's impossible to stop him over 90 minutes," Mourinho said, "… these kind of players will always have a moment or a couple of moments where they end up showing why they are so good.

"Mesut is a phenomenal player, one of these players that you buy to complete the puzzle of your team. You don't need time with him, you need nothing. The player just arrives. His quality and his maturity and his leadership … you put him in and you know automatically your team becomes better.

"There are many ways to improve your team. One of them is to work with young players and another is to go directly to the market and buy one of these finished products. Arsenal had the chance to do it with Mesut and they did very well."