Arsenal striker Dennis Bergkamp revealed United's manager Alex Ferguson had blundered to sell their defender Jaap Stam and that is going to cost them the title this season, reported The Sun.

Bergkamp, 32, believes Stam is one of the best defenders worldwide. But Ferguson sold Stam to Lazio last August for 16.5 million and a month before Arsenal coach Arsene Wenger bought Sol Campbell from Tottenham. Now Bergkamp is happy he will not face Stam when Gunners try to fulfill the second part of their plan to make a Double this year playing against United at Old Trafford.

"Sol Campbell is one of the best three central defenders in the world. He is so strong and we're very lucky we've got him to add to all our other defenders. I would also rate Stam as one of those best three defenders. I know him pretty well and I've also played against him. He has similar qualities to Sol - both are strong, pacy and can be nasty as well. Stam did well for Manchester United. I don't know statistically how many they conceded with and without him - but they've been more open at the back this season than in others and a tight defence has been their biggest strength in the past. If that's down to selling Stam or the players who are there now, I don't know. But I'm quite happy Stam's not going to be there on Wednesday. Sol has been a big plus for us and he's had a very good season - and he's still quite young. He was so impressive when I played against him at Tottenham," said Bergkamp.

Arsenal need a point at Old Trafford to secure the title. If that happens Gunners will finish the season without an away defeat.

"The cup final says a lot about our season. You can compare us to Liverpool last year when they won three cups and qualified for the Champions League. They just won their games and won every cup, when people were asking 'They have so many games, can they do it?' We seem to be in that zone as well now. We do feel invincible at the moment, really. Sometimes it just seems to be happening for us without us even trying that hard. We could have lost the final but that sort of luck is something you force throughout the season. Ferguson said he thought Chelsea would win the cup final. If it is just mind-games, then we are quite strong and experienced enough to concentrate on our own games. It was very important to win at Bolton and give ourselves two chances of winning the title, which takes a little bit of the pressure off the Wednesday match. But if we could do it at Old Trafford it would be great. We haven't lost away all year and we don't want to do that now against United. If we keep it going it'll mean we've won the title. It's been a good thing for us to strengthen the squad with players like Campbell and Giovanni van Bronckhorst. We've made the squad bigger and that's paid off this season. The idea is to dominate for the next few years. We don't want the same situation as in 1998 when we dropped back again for three seasons. If we want to dominate we have to do it now because we have the players who are at the right age," added the Dutch player.