Louis van Gaal said earlier in the week that FA Cup defeat at Derby could cost him his job - but a routine win over the Rams means the under-fire Manchester United boss will spend the weekend opening up a celebratory bottle of wine instead of packing away his desk.

The 64-year-old admitted in the lead up to United's fourth-round clash with the Sky Bet Championship promotion hopefuls that a loss to the Rams could spell the end of his Old Trafford tenure as supporters continue to grow weary of his perceived negative tactics.

But he appears to have secured a stay of execution as goals from Wayne Rooney, Daley Blind and Juan Mata earned the Red Devils a fully-deserved 3-1 win over Derby - who had equalised in the first half through George Thorne.

And the victory, which ensures 11-time winners United are the first name into the hat for the fifth-round draw, will now celebrate by opening an expensive bottle of wine with his wife - a gift from the Reds' chief executive Ed Woodward after Van Gaal led United to a win over Liverpool earlier in the month.

"I come back and my wife is at home because she was in the Netherlands, and the wine is already open," he said.

"We drink a nice bottle of wine, probably the most expensive wine, because I have received that from Ed Woodward.

"Because I get always expensive wine when we beat an opponent of out the top six. I don't want to mention the name (of the wine) because it is a little bit extravagant."

Despite the toasting of his side's success, Van Gaal stopped short of heaping praise on his players, who had dominated for large swathes of their east midlands encounter.

Anthony Martial enjoyed one of his best performances in recent weeks but even the France international was not immune to Van Gaal's post-match analysis.

"The first 20 minutes he was very bad," he said of his summer signing from Monaco.

"Maybe you have noticed that because everyone is saying how fantastic he played, (he should be) man of the match.

"But you have to play 90 minutes good. I have said that already to him otherwise I could not say it to you. But after that first 20 minutes he was fantastic."

United scored three goals when in recent weeks they have largely been criticised for their lack of cutting edge in front of goal and the number of chances they have created.

But Van Gaal insists there is no change in approach or philosophy and his players were simply allowed to play their game.

"They didn't have more freedom, they have always freedom from me," he added when asked if his players were allowed to play with more freedom.

"You want to write that but then don't ask (a) rhetorical question. For you (it is) obvious (there is) more freedom? No. Same philosophy, same training session past three days. I give my players always freedom, building up attack is more freedom than defending.

"Defending I have a game plan. I am not pleased with how you are twisting my words."

Meanwhile, Paul Clement admitted Derby were beaten by the better side on the night but was pleased with how they offered a test to United.

"I don't think we were unlucky," the Rams boss said.

"I though Man United deserved to win the game and played well for a team that is supposed to be in disarray and lacking confidence.

"They controlled the game in terms of possession and were clinical with their movement and finishing and overall deserved it.

"But I felt our team gave them a good game, it wasn't all one-way traffic and we scored a good goal in the first half.

"I would have just liked it to have stayed at that scoreline for long and let the belief grow and take it into the final 15 minutes and then you never know."