Manchester United's Robin van Persie celebrates completing his hat-trick against Olympiakos during their Champions League last-16, second-leg match at Old Trafford on Wednesday.

Embattled Manchester United manager David Moyes insisted he was not under pressure after his side's stirring comeback against Greek champion Olympiakos took it into the Champions League quarterfinals.

Moyes enjoyed a rare night of success at Old Trafford on Wednesday as United overturned a 2-0 deficit from the first leg of its last-16 tie with a 3-0 victory built around a Robin van Persie hat-trick.

With United 18 points off the lead and 12 points shy of the top four in the Premier League after a chastening 3-0 loss to Liverpool on Sunday, the former Everton manager's position has come under scrutiny.

Some British media reports suggested his job would remain at risk regardless of the outcome of the Olympiakos tie, but he said he was confident he retained the full support of his employers.

"I'm not feeling any pressure from inside the club," he said.

"It' i coming from you people. We know the job we have to do. It is probably bigger than what I thought when I first came to the club.

"There are stories of this player falling out, or that one falling out, but it is rubbish. People are looking for reasons why we are not doing well, but it is only because we have not been playing well."

United had never previously overturned a two-goal deficit in the Champions League knockout phase, but Moyes was unwilling to describe the success as a potential watershed moment.

"People will probably think it is a turning point in people's careers, but I didn't see it like that because the club doesn't see it like that," said the Scot, who signed a six-year contract last year.

"I see myself here for a long time. I think we know we have a lot of work to do, but it is a great result and we want to stay in the competition."

Van Persie broke the deadlock with a 25th-minute penalty after he had been bundled over by Jose Holebas and then leveled the aggregate score in first-half injury time by converting a low center from Wayne Rooney.

The Dutch striker settled the tie with a free kick seven minutes into the second period, but United had to endure several close shaves and was indebted to some assured shot-stopping by goalkeeper David de Gea.

Van Persie was stretchered off in the dying stages after taking a blow to the back of his knee, but Moyes played down the extent of the injury, saying it was "hopefully not too bad".

He also paid tribute to 40-year-old midfielder Ryan Giggs, who showcased a magnificent range of passing, including raking passes that set up his side's first two goals.

United will learn the identity of its quarterfinal opponent on Friday, and while its domestic travails make winning the title seem very unlikely, Moyes still believes the club could go all the way.

"We probably now will go into it as underdogs in a lot of the games," he said. "Hopefully we can do it. I don't see any reason why not.

"I think this club is capable of it. If we play to our capabilities, which we have not done too often, I think we will be a match for any team."

Olympiakos has now lost on all of its 12 visits to England, but having emerged from a group containing Paris Saint-Germain and Benfica before almost upsetting United, coach Michel was eager to emphasize the positives.

"I'm very disappointed, because when I saw the players afterward, it wasn't a nice sight to see," said the former Real Madrid midfielder, whose side retained the Greek league title last Saturday.

"But overall, it was a good season in Europe. We have to look forward."