Arsène Wenger's will to win on his own terms is leading to mediocrity

Arsène Wenger has always followed his own path, but he is leading Arsenal into mediocrity. A largely justified reputation as a visionary distracts people from noticing the most basic flaws in the team. With 25 Premier League games completed, the 2-0 defeat at Stamford Bridge means they have conceded 30 goals. That equals the worst defensive performance Wenger has presided over since his arrival in the autumn of 1996.

Statistics of that sort are far from bloodless, and Arsenal have been wounded. Never before in the history of the Premier League have they lost all four of their encounters with Chelsea and Manchester United. The Old Trafford defeat may have been undeserved, but there is no quibbling with the aggregate score. Arsenal must be dazed after the 10-2 thumping from Carlo Ancelotti and Sir Alex Ferguson's teams.

In a practical sense, nothing grave has befallen the club. Arsenal are very likely to qualify for next season's Champions League and their current interest in the competition is genuine. They are favourites to get the better of Porto in the last-16 tie that starts next week. The real harm is done to fans, who are starting to feel undernourished on a diet of idealism, and, less gravely, to neutrals who would prefer to see more than just a pair of contenders for the Premier League title.

Two seasons ago Arsenal topped the table at this juncture and appeared reasonably well-equipped. There was to be terrible misfortune in Eduardo da Silva's broken leg at Birmingham City in February 2008. He had notched a dozen goals in that campaign, but has understandably had less impact since his return. He, however, was not to be the only person whose loss would be felt. Jens Lehmann and Gilberto Silva left at the end of that campaign.

It may have been time for them to go, even if the Brazilian was still capable of commanding a place in his national team when England were beaten three months ago, but they have not been replaced satisfactorily. Manuel Almunia has none of the command that Lehmann exuded, and seems to spread unease in the defence. Where holding midfielders are concerned, Arsenal now have no experienced candidates. United and Chelsea have been permitted to notch goals on the break in successive weekends.

The club needs to find a starting point, but Wenger has been disdainful of lesser prizes that might actually be alluring to supporters. Arsenal virtually inflict FA Cup defeats on themselves, and a lightweight selection went out at Stoke City last month. This policy is intended to conserve energy for more important challenges, but getting knocked out does appear to be dispiriting. Since leaving the Britannia Stadium, Arsenal have not won in three games.

Those matches have been particularly tough, but the pattern is also familiar. In 2008, Wenger sent out a weakened line-up against United in the FA Cup and watched as they were crushed 4-0. Injuries were a factor but some of the absentees faced Milan four days later. If Wenger had been writing off the FA Cup it proved to be an error as he helped United to develop the momentum that ultimately took them past the then leaders, Arsenal, in the league.

It is traditional and often fair to point to Arsenal's lack of means, particularly while they concentrate on paying off the cost of the Emirates, but there are limitations, too, that are self-imposed and idiosyncratic. The deals that saw Kolo Touré and Emmanuel Adebayor move to Manchester City for a total of £41m was extraordinarily good business for Arsenal and that unanticipated sum was a windfall. The money, all the same, was not used to bring in the centre‑forward who was so badly needed.

There was plenty of time to act since they left Arsenal when over a month of the transfer window remained. Wenger then spoke of wishing to bring in a striker in January, but no business was done. Though the manager was on a demanding mission, it is for his ingenuity and knowledge that he is employed. Sympathy for the harm done by the loss of Robin van Persie to ankle trouble in November is tempered by the recognition that Wenger knew the Dutchman was injury prone.

Arsenal remain the most idiosyncratic of Europe's major clubs. Wenger, with his intelligence and commitment to streamlined football, has endowed them with a status they never enjoyed before but there are days, too, when it seems that success will only be accepted on his pure and personal terms.