SUNDERLAND, United Kingdom (AFP) - Louis van Gaal dismissed suggestions that his side's 2-1 Premier League defeat at Sunderland on Saturday has put him under even more pressure as Manchester United manager.

An unfortunate 82nd-minute own goal by David de Gea condemned United to a loss that prevented them from closing the six-point gap that separates them from the Champions League places.

Van Gaal's position has been the subject of speculation for weeks and reports emerged last week that United have approached former Chelsea manager Jose Mourinho to replace the 64-year-old Dutchman.

But when asked if the defeat at the Stadium of Light put him under more pressure, he replied: "No. I have to do my work and I do my work to my utmost best and I cannot do more.

"I shall prepare my players against Midtjylland (in the Europa League) 100 percent and I shall do that always."

Defeat was doubly frustrating for United as - with fourth-place Manchester City hosting Tottenham Hotspur and leaders Leicester City visiting third-place Arsenal on Sunday - they had a chance to make ground on the top four.

United were also pegged back by a late goal in their previous game, conceding a stoppage-time equaliser in a 1-1 draw at Chelsea, and Van Gaal conceded that their top-four hopes were fading.

"It will be very difficult now because we give five points away, Chelsea and now," he said. "It's too much at this time."

Van Gaal agreed when it was put to him that United's best chance of reaching the Champions League is to win the Europa League.

"After this match, I think that is the best route," he said. "But that's not so easy because a lot of very good teams are participating in this event."

Tunisian home debutant Wahbi Khazri put Sunderland ahead in the third minute with a free-kick from wide on the left that eluded everyone and crept in at the far post.

Anthony Martial equalised before half-time, but Sunderland regained the lead when Martial's attempt to clear Lamine Kone's header from Khazri's corner off the line hit De Gea's elbow and rolled over the line.

A crestfallen Wayne Rooney admitted that United now face a struggle to secure a place in the top four and with it an immediate return to the Champions League following their group-stage exit this season.

"It will be difficult to get into the top four now," the United captain told BT Sport. "We have to somehow move on."