Nine years without a trophy means you better mind the gap, Arsène Wenger

Lose today and Arsenal will be as far off the top as at any time since 2004

Nine years ago last Thursday, Arsenal won the Premier League at White Hart Lane, held to a 2-2 draw but continuing the unbeaten record they then maintained for the remaining four games of the season to inscribe themselves in football history as The Invincibles.

The notion that they would finish 12 points behind Chelsea the following season, even with a brash new upstart called Jose Mourinho coming on to the scene, seemed far-fetched; as for reaching 2013 having won one FA Cup final on penalties and no more trophies at all... "unthinkable" hardly covers it.

Yet here is Arsène Wenger, still in charge and trying to talk away his team's latest deficit behind the League leaders, currently standing at 21 points. If Manchester United were to win at the Emirates this afternoon, the margin of 24 would equal the furthest that Arsenal have finished in arrears since their last success. In that time they have only once (in 2008) ended up within 10 points of the winners, and the average gap has been 15 points.

Wenger frequently argues that there has been another sort of consistency. "What we have managed during this period is not finishing 12th or 16th in one season, we have always been in the top four," he said on Friday. "I don't know if you read the statement of John Terry when [Chelsea] played in the Europa League. He said: 'There is only one thing that matters for us – to finish in the top four'. That is a real target. We have always been in there. We missed something, we were short a few times to win the title. And I am sure we will be back again."

Certainly, 15 successive seasons in the Champions' League is a fine record. On the other hand, Terry has lifted 11 major trophies but no Arsenal captain has lifted any since Patrick Vieira. With four games left, Arsenal's only target is to extend that European run, preferably by taking third and avoiding qualifying in August. Lose today and they would be vulnerable to Chelsea, at home to Swansea today, and Tottenham.

There have several talented players who served the club well but did not win a trophy, while Robin van Persie only won an FA Cup medal before moving on to better his chances. Wenger would like it known that for all his United goals, Arsenal have managed almost as many as last season, with four players having reached double figures. In Olivier Giroud's three-match absence, he now needs Theo Walcott (18 goals) or Lukas Podolski (14) to keep up the ratio.

As for the Dutchman's impact at Old Trafford, Wenger says: "Look, Man United won 20 championships. They won a few without Robin van Persie. They lost only on goal difference last year and if QPR did not know that they were safe [towards the end of the final match], they would have won it last year. You can say that Robin had an impact but do you really think that I am surprised?"

Sir Alex Ferguson, meanwhile, has listed Van Persie among a team of 11 great strikers he has had at United from Mark Hughes and Brian McClair onwards, and praised him as a man as well as a footballer. "It took him three or four months to get his personality into the training sessions, but he lives the right way, he trains the right way," Ferguson said. He mentioned United's victory over Arsenal in the Champions' league semi-final of 2009. "The boy [Kieran] Gibbs slipped for one of the goals. The only Arsenal player who went up to Gibbs was Van Persie. He put his arm round his shoulder – and he's getting that influence on the young players here."

With 24 League goals after last Monday's hat-trick against Aston Villa, Van Persie has been a key element this season – whatever Wenger believes.

Arsenal v Manchester United is on Sky Sports 1 today, kick-off 4pm