A meeting between Arsenal and Manchester United is usually not only one of the defining matches of the season but also an opportunity for Arsene Wenger and Alex Ferguson to demonstrate their tactical superiority over other Premiership managers.

But when the teams meet tomorrow at Highbury both sets of supporters will be casting nervous eyes as much towards the dugouts as the pitch for further evidence of declining powers.

Though both teams are still a warm order for the title and are among the 16 elite clubs contesting the second stage of the Champions League, such are the standards their managers have set that for the first time their judgments are being questioned by fans and even rivals such as Leeds's David O'Leary.

United, who sailed to the top of the Premiership on September 9th last year and stayed there to the end, have made their worst start since 1997-98.

That was the season, of course, when Arsenal won the title in Wenger's first full year in charge. But Wenger, who is adamant he is staying despite not signing a new contract and who now looks more Strachan than suave when urging his men on from the sidelines, disturbingly talked about jumping off a high building when his side surrendered another late goal last week at Tottenham.

His claim that "we should be six points clear of everybody else" was also the statement of a frustrated, disillusioned man rather than one who used to be renowned for his rationality.

Ferguson has become so upset by personal criticism he is now refusing to talk to the press, preferring to reply in what amounted to a poison-pen letter in the United programme for last Saturday's game against Leicester. "They say the empire is crumbling, but empires crumble from within and our foundations are rock solid," he wrote. "Inevitably, I have been a target for much of the criticism. I think some people have been quietly waiting for an opportunity to have a go and have decided that this is the moment to let fly with both barrels."

No paranoia there, then, though Ferguson conceded his team sank below acceptable standards against Liverpool in their previous league game and said Tuesday's Champions League tie against Bayern in Munich would be the litmus test for their season.

United came away with a creditable 1-1 draw, a result Arsenal would die for away from home in Europe, but the match again underlined the failings of their defence.

Since Ferguson encouraged Steve McClaren to take the Middlesbrough job when it was clear the England coach would not become his Old Trafford successor, he has lacked a restraining voice in his ear, stubbornly refusing to refine a split-striker system that is not working.

It led to Paul Scholes's refusal to travel to Arsenal for a League Cup game, insubordination that would have been unthinkable 12 months ago. Yet Scholes was rewarded by being restored to his favoured midfield role for the victory over Leicester, proving himself more effective there.

There are other signs of boat-rocking at the club, with Andy Cole and Dwight Yorke complaining that they do not start enough games. Brilliant though Ferguson's summer purchase Juan Sebastian Veron is, neither manager has proved adept at rebuilding, Wenger in particular failing to replace the marvellous, but ageing, back four he inherited. Admittedly, injuries have played a part, with Arsenal's central defenders - and goalkeepers, which means the untried Stuart Taylor (20), will make his Premiership debut tomorrow.

Wenger said: "Matthew Upson, Sol Campbell and Lauren did not know each other at the start of the season so it is not possible for them to find the same stability as the defenders that played together for 10, 15 years."

But Wenger's summer signings have failed to strengthen his hand. Richard Wright, now injured, needed a rest anyway, Giovanni van Bronckhorst has been a model of mediocrity in midfield or at left-back, Campbell is showing only glimpses of his best form, and Francis Jeffers' future looks in serious doubt after he damaged the same ankle that hampered his career at Everton.

As for Junichi Inamoto, he may sell a lot of shirts in Japan but has yet to wear one on his own back.

Patrick Vieira was castigated in the summer for ridiculing the men Wenger had signed. But so far the midfielder appears to have been right. The worst fear of Arsenal fans is that not only Vieira will leave but Wenger as well, closely followed out of the marble halls by their fellow Frenchmen Robert Pires and Thierry Henry.