Arsène Wenger has said Arsenal may have to break the bank to secure Mesut Özil to a new long-term contract and also prove to him the club can satisfy his ambitions by winning the league title. The midfielder’s deal expires in the summer of 2018 and negotiations are continuing over fresh terms.

Wenger was asked to give an update on the situation after Arsenal’s 3-2 home win against Swansea City on Saturday – in which Özil scored his team’s third goal – and it was plain the parties remain a distance apart. Özil earns a reported basic wage of £140,000 a week but he is seeking a substantial rise to reinforce his status as one of the club’s marquee players.

“I don’t think he needs convincing [to stay],” Wenger said. “He wants to stay here. If you have a good bank, call me.”

It was put to Wenger that he had made it sound as if the club and player were a long way apart in their valuations. “We keep that discreet,” he replied. “At due time we will come out with that. Am I confident he will sign? It’s not my main worry now. We want to keep our best players, of course. The more I say that, the more he is in a stronger position.”

Özil is Arsenal’s record signing, having joined from Real Madrid in the summer of 2013 for £42.5m. He turned 28 on Saturday and he is determined to add to the one league title he has won in his career – the Spanish championship with Real in 2011-12.

Wenger said: “It’s not just money. Arsenal can win titles, of course. But that’s what we have to show. We are in a league where Man City, Man United, Liverpool, Tottenham, Chelsea, everybody, fights and you cannot guarantee that to anybody.”

Özil’s goal on Saturday – a beautifully executed volley – was his third of the season and Wenger said he wanted to see him score more. Özil’s best return over a season for Arsenal was the eight he scored last time out. “When you see Özil finishing [against Swansea], you think a little bit that he doesn’t take his chances to shoot enough,” Wenger said.

“When you see him in training, he scores basically when he wants. You speak with the keepers and he’s one of the most difficult players to predict where he’ll put the ball. I’m happy that he scored and I hope that gives him the taste to try more.

“He is 28 now. In the next four years he has to combine style and efficiency. He had always fantastic style; fantastic efficiency in assists. But efficiency in his position is also finishing and he has that in the locker. It’s not that he hasn’t got it.”

Arsenal’s victory against Swansea was their sixth in succession in the Premier League and it took them level on points with the leaders, Manchester City. “If I say ‘No,’ you will think I am absolutely mad,” Wenger said, when asked whether Arsenal could win the title.

“After the first game against Liverpool [a 4-3 home defeat] you could not predict that we would be where we are today. What is at stake for us is to show that we can maintain that run on a longer distance. We are also conscious that we still have some things to improve in our game. We have to go a step higher up to go the next level.

“We need to keep our rigorous attitude. We are a playing side and you see that. We are 2-0 up [against Swansea] and, suddenly, the playing takes over from the rigorous attitude. We have always to do what the game demands and, maybe, we were a bit too easy at 2-0, thinking: ‘OK, we’ll win again.’ In the Premier League we have to be conscious in every single game.”