Manchester United manager David Moyes on Tuesday brushed off suggestions that his position is under threat ahead of a crunch Champions League game against Olympiakos on Wednesday.

"My future has not changed one bit," he told reporters at Old Trafford who pressed him about United's struggles this season.

"We know we have put ourselves in a poor position, but we have belief," added Moyes.

Trailing 2-0 to the Greek side in the last 16, United must become only the sixth team to overturn a deficit of two goals or more in the competition's knockout phase to go through.

Since Moyes took over this season, United have also struggled to get a qualifying place for next season's Champions League. They are now 12 points below the top four in the Premier League after Sunday's 3-0 loss at home to Liverpool. They are out of both domestic cup competitions.

The team's travails prompted reports in British newspapers on Tuesday that Moyes could be at risk if United are eliminated by Olympiakos. Some newspapers said he has three games to turn around United's fortunes.

But Moyes insisted that his position is secure.

"I have a great job, and I know the direction I want to go in. We know we have put ourselves in a poor position, but we have belief."

Asked if he had been given assurances by the United hierarchy that there is no threat, Moyes replied: "The biggest assurance is that they let me get on with the job.

"They never discuss it (his future). We talk about the future, we make big plans going forward. That is why they gave me a six-year contract. This is not a club that works on a short-term vision; it is a long-term one."

United's supporters continued to provide vocal backing to the team during the chastening loss to Liverpool and Moyes remains confident that he is capable of restoring their team to former glories.

"I actually think they have seen some defeats they wouldn't have expected and they have stuck with the team throughout," said the former Everton manager.

"They have seen great success here in the past and will see great success again in the future. This club is the biggest club in the world. It might not feel it today, but it will rise again."

Ferguson 'incredibly supportive'

United have lost seven of their 14 games since the start of 2014, but Moyes says that he continues to receive support from his storied predecessor Alex Ferguson, who personally recommended his appointment.

"He has been incredibly supportive," Moyes said. "I speak with him regularly and see him at the games. He's very supportive.

"He told me before I came in that it was a difficult job, but he is always here to help. (Director) David Gill, (vice chairman) Ed (Woodward), all the board are very supportive."

Defender Patrice Evra appeared beside Moyes at Tuesday's press conference and while he was at a loss to explain United's current predicament, he told the fans to expect a much improved performance against Olympiakos.

"When you win, you win together. When you lose, you lose together," said the France left-back.

"It has been a difficult season for everyone. We are not used to losing games, but everyone fights for this club, everyone loves this club.

"In life, you always have a second chance. I am not going to tell you we are going to qualify, but I promise we are going to fight and the fans will be proud of us after the game."

Centre-backs Chris Smalling (hamstring) and Jonny Evans (calf) are both expected to miss Wednesday's match after sitting out training on Tuesday, while club-record signing Juan Mata is cup-tied.

Moyes also revealed that the club's Japanese playmaker Shinji Kagawa, who last started a game on January 22, would play some part in the match.

"Shinji is an important player for us," he said.

"It has been a difficult time and he has not played as often as he would have liked. Shinji is someone we like and will definitely be involved at some point tomorrow."