Alex Ferguson insists his Manchester United champions will keep their intensity right until the end of the season.

The United boss saw a Robin van Persie penalty and a battling United performance deprive Arsenal of two vital points in their quest for Champions League qualification with a 1-1 draw at the Emirates stadium on Sunday.

And Ferguson promises Chelsea will face an equally determined United at Old Trafford next weekend, even though United cannot now post a record Premier League points total.

Ferguson said: "We have got Chelsea next week, they are fighting for a Champions League place and we have to honour the rest of the teams who are trying to get there, like we did (against Arsenal).

"Nobody could say we relaxed too much, I thought we had the edge to the game in the second half."

Van Persie was afforded a guard of honour on to the Emirates pitch by the Arsenal players but was booed by Gunners fans throughout the match on his first return to Arsenal since joining United for £24million last summer.

"Nobody could say we relaxed too much, I thought we had the edge to the game in the second half." Ferguson on the performance against Arsenal

The jeers were loudest as he stood up to stroke the penalty past Arsenal goalkeeper Wojciech Szczesny just before half-time after he had been brought down in the area by full-back Bacary Sagna and referee Phil Dowd pointed to the spot.

Ferguson praised Van Persie's equilibrium.

"He kept his nerve, that was important," said Ferguson.

"It was a difficult time for him, the chanting from the fans does not help, but he kept his cool."

United had most of the clear-cut chances after Theo Walcott had put Arsenal ahead with a crisp shot past goalkeeper David De Gea after just two minutes in a match which started at a breakneck pace and saw five United players booked.

Ferguson said: "I thought the referee found it difficult and the game was running away from him, he found it difficult to control.

"Once we started getting some momentum going and a bit of heart, we looked like the team to win.

"We had some good headers in the first half, the goalkeeper has made a great save from one of them and Phil (Jones) has missed the other two.

"In the second half Wayne had a chance with a header, and time and again the final ball let us down. We were the team making the chances. Credit to Arsenal, they kept fighting which is what we expected."

The draw leaves Arsenal in fourth spot with three matches remaining and manager Arsene Wenger said:

"If we win our other games it will be enough. I am convinced we will be there (in the top four) but there is no room for dropping points."