Arsène Wenger says that Manchester United have been "a bit lucky until now" to remain undefeated in the Premier League, but he feels that they will not begin to think about emulating Arsenal's Invincibles until they enter the final five games of the season.

The Arsenal manager, who counts his team's unbeaten title success in 2003‑04 as his finest achievement, said it is impossible to predict whether United would follow suit this time out. But what he did know was that if Sir Alex Ferguson's men stood a chance to do so in the final stretch, his team would be in the position to stop them.

One or two of Wenger's Invincibles have said in private they would hate it if United were to go unbeaten, as it would take some of the shine off what they achieved. Arsenal entertain United at the Emirates on 30 April, with four matches of the season remaining.

"Do you ask me can they still do it?" Wenger said ahead of his side's clash with Wigan today. "Certainly, because they have not been beaten yet. Have they been a bit lucky until now? Certainly, but we'll see. I don't know more than you. You really think about winning the championship but with five games to go, you think about: 'Oh, we can add something to that.' That's what happened with us. But you don't think about that with 16 games to go."

United have 17 games to go and their record after the first 21 is similar to Arsenal's from 2003-04; United have nine draws while Arsenal had seven. Moreover, there has been the element of good fortune that Wenger knows, from experience, is crucial.

United have struggled at times away from home and their 2-1 win at West Bromwich Albion, when Peter Odemwingie missed a 63rd-minute penalty with the score at 1-1, could easily have gone the other way. Arsenal might have lost in September 2003 at Old Trafford but the United striker Ruud van Nistelrooy missed an injury-time penalty in the 0-0 draw.

"At West Brom, for example," Wenger said, when asked where he felt United had been particularly lucky this season. "But overall, I'm more concerned by our own performance. What is important is to beat Man United and we will only have the chance, with the run that they are on, if we do exceptionally well until the end of the season.

"So I focus more on that, knowing that they have a difficult schedule as well. If they have five games to go and they are still unbeaten, come back to me and I'll say 'Now, they can do it.'"

Arsenal have agreed to loan Aaron Ramsey to Cardiff City until 26 February. The midfielder, who joined Arsenal from Cardiff in 2008, is due to sign tomorrow morning.