MANCHESTER, ENGLAND - MAY 17: Cars are searched at security check points outside Old Trafford prior to the Barclays Premier League match between Manchester United and A.F.C. Bournemouth at Old Trafford on May 17, 2016 in Manchester, England. (Photo by Alex Livesey/Getty Images)

MANCHESTER, ENGLAND - MAY 17: Cars are searched at security check points outside Old Trafford prior to the Barclays Premier League match between Manchester United and A.F.C. Bournemouth at Old Trafford on May 17, 2016 in Manchester, England. (Photo by Alex Livesey/Getty Images)

Manchester United U21's James Weir and manager Warren Joyce parade the trophy for winning the Barclays U21 Premier League during the Barclays Premier League match at Old Trafford, Manchester. PRESS ASSOCIATION Photo. Picture date: Tuesday May 17, 2016. See PA story SOCCER Man Utd. Photo credit should read: Martin Rickett/PA Wire. RESTRICTIONS: EDITORIAL USE ONLY No use with unauthorised audio, video, data, fixture lists, club/league logos or "live" services. Online in-match use limited to 75 images, no video emulation. No use in betting, games or single club/league/player publications.

Manchester United U21's James Weir and manager Warren Joyce parade the trophy for winning the Barclays U21 Premier League during the Barclays Premier League match at Old Trafford, Manchester. PRESS ASSOCIATION Photo. Picture date: Tuesday May 17, 2016. See PA story SOCCER Man Utd. Photo credit should read: Martin Rickett/PA Wire. RESTRICTIONS: EDITORIAL USE ONLY No use with unauthorised audio, video, data, fixture lists, club/league logos or "live" services. Online in-match use limited to 75 images, no video emulation. No use in betting, games or single club/league/player publications.

Stewards search fans in a security check before the Barclays Premier League match at Old Trafford, Manchester. PRESS ASSOCIATION Photo. Picture date: Tuesday May 17, 2016. See PA story SOCCER Man Utd. Photo credit should read: Martin Rickett/PA Wire. RESTRICTIONS: EDITORIAL USE ONLY No use with unauthorised audio, video, data, fixture lists, club/league logos or "live" services. Online in-match use limited to 75 images, no video emulation. No use in betting, games or single club/league/player publications.

Stewards search fans in a security check before the Barclays Premier League match at Old Trafford, Manchester. PRESS ASSOCIATION Photo. Picture date: Tuesday May 17, 2016. See PA story SOCCER Man Utd. Photo credit should read: Martin Rickett/PA Wire. RESTRICTIONS: EDITORIAL USE ONLY No use with unauthorised audio, video, data, fixture lists, club/league logos or "live" services. Online in-match use limited to 75 images, no video emulation. No use in betting, games or single club/league/player publications.

A mounted police presence outside the ground before the Barclays Premier League match at Old Trafford, Manchester. PRESS ASSOCIATION Photo. Picture date: Tuesday May 17, 2016. See PA story SOCCER Man Utd. Photo credit should read: Martin Rickett/PA Wire. RESTRICTIONS: EDITORIAL USE ONLY No use with unauthorised audio, video, data, fixture lists, club/league logos or "live" services. Online in-match use limited to 75 images, no video emulation. No use in betting, games or single club/league/player publications.

Manchester United manager Louis van Gaal and assistant Ryan Giggs (right) during the Barclays Premier League match at Old Trafford, Manchester. PRESS ASSOCIATION Photo. Picture date: Tuesday May 17, 2016. See PA story SOCCER Man Utd. Photo credit should read: Martin Rickett/PA Wire. RESTRICTIONS: EDITORIAL USE ONLY No use with unauthorised audio, video, data, fixture lists, club/league logos or "live" services. Online in-match use limited to 75 images, no video emulation. No use in betting, games or single club/league/player publications.

MANCHESTER, ENGLAND - MAY 17: David De Gea of Manchester United poses with the player of the year trophy prior to the Barclays Premier League match between Manchester United and AFC Bournemouth at Old Trafford on May 17, 2016 in Manchester, England. (Photo by Alex Livesey/Getty Images)

MANCHESTER, ENGLAND - MAY 17: Antonio Valencia of Manchester United is chased by Charlie Daniels of Bournemouth during the Barclays Premier League match between Manchester United and AFC Bournemouth at Old Trafford on May 17, 2016 in Manchester, England. (Photo by Michael Regan/Getty Images)

MANCHESTER, ENGLAND - MAY 17: James Weir and Devonte Redmond and Manchester United team mates celebrate with Barclays Under-21 Premier League trophy prior to the Barclays Premier League match between Manchester United and AFC Bournemouth at Old Trafford on May 17, 2016 in Manchester, England. (Photo by Alex Livesey/Getty Images)

Manchester United's Dutch manager Louis van Gaal arrives for the rescheduled English Premier League football match between Manchester United and Bournemouth at Old Trafford in Manchester, north west England, on May 17, 2016. The match, originally scheduled for May 15, was called-off minutes before kick-off following the discovery of a suspect device, which turned out to be a fake bomb left in the stadium by mistake after a terror training exercise. / AFP PHOTO / Lindsey PARNABY / RESTRICTED TO EDITORIAL USE. No use with unauthorized audio, video, data, fixture lists, club/league logos or 'live' services. Online in-match use limited to 75 images, no video emulation. No use in betting, games or single club/league/player publications. / LINDSEY PARNABY/AFP/Getty Images

MANCHESTER, ENGLAND - MAY 17: James Weir and Manchester United team mates celebrate with Barclays Under-21 Premier League trophy prior to the Barclays Premier League match between Manchester United and AFC Bournemouth at Old Trafford on May 17, 2016 in Manchester, England. (Photo by Alex Livesey/Getty Images)

MANCHESTER, ENGLAND - MAY 17: Wayne Rooney of Manchester United and Marc Pugh of Bournemouth battle for the ball during the Barclays Premier League match between Manchester United and AFC Bournemouth at Old Trafford on May 17, 2016 in Manchester, England. (Photo by Michael Regan/Getty Images)

MANCHESTER, ENGLAND - MAY 17: Marcus Rashford of Manchester United looks on during the Barclays Premier League match between Manchester United and AFC Bournemouth at Old Trafford on May 17, 2016 in Manchester, England. (Photo by Alex Livesey/Getty Images)

MANCHESTER, ENGLAND - MAY 17: Wayne Rooney of Manchester United celebrates with Anthony Martial (9) and Jesse Lingard (35) as he scores their first goal during the Barclays Premier League match between Manchester United and AFC Bournemouth at Old Trafford on May 17, 2016 in Manchester, England. (Photo by Alex Livesey/Getty Images)

MANCHESTER, ENGLAND - MAY 17: Wayne Rooney of Manchester United celebrates with Anthony Martial as he scores their first goal during the Barclays Premier League match between Manchester United and AFC Bournemouth at Old Trafford on May 17, 2016 in Manchester, England. (Photo by Alex Livesey/Getty Images)

Manchester United's English midfielder Ashley Young (2L) shoots past Bournemouth's Australian goalkeeper Adam Federici (C) to scores his team's thrid goal during the rescheduled English Premier League football match between Manchester United and Bournemouth at Old Trafford in Manchester, north west England, on May 17, 2016. The match, originally scheduled for May 15, was called-off minutes before kick-off following the discovery of a suspect device, which turned out to be a fake bomb left in the stadium by mistake after a terror training exercise. / AFP PHOTO / Lindsey PARNABY / RESTRICTED TO EDITORIAL USE. No use with unauthorized audio, video, data, fixture lists, club/league logos or 'live' services. Online in-match use limited to 75 images, no video emulation. No use in betting, games or single club/league/player publications. / LINDSEY PARNABY/AFP/Getty Images

Manchester United manager Louis van Gaal after the Barclays Premier League match at Old Trafford, Manchester. PRESS ASSOCIATION Photo. Picture date: Tuesday May 17, 2016. See PA story SOCCER Man Utd. Photo credit should read: Martin Rickett/PA Wire. RESTRICTIONS: EDITORIAL USE ONLY No use with unauthorised audio, video, data, fixture lists, club/league logos or "live" services. Online in-match use limited to 75 images, no video emulation. No use in betting, games or single club/league/player publications.

MANCHESTER, ENGLAND - MAY 17: Ashley Young of Manchester United (18) celebrates with Michael Carrick (16) and team mates as he scores their third goal during the Barclays Premier League match between Manchester United and AFC Bournemouth at Old Trafford on May 17, 2016 in Manchester, England. (Photo by Michael Regan/Getty Images)

Manchester United's Michael Carrick on the pitch with his family on the pitch during the Barclays Premier League match at Old Trafford, Manchester. PRESS ASSOCIATION Photo. Picture date: Tuesday May 17, 2016. See PA story SOCCER Man Utd. Photo credit should read: Martin Rickett/PA Wire. RESTRICTIONS: EDITORIAL USE ONLY No use with unauthorised audio, video, data, fixture lists, club/league logos or "live" services. Online in-match use limited to 75 images, no video emulation. No use in betting, games or single club/league/player publications.

MANCHESTER, ENGLAND - MAY 17: Louis van Gaal manager of Manchester United applauds the crowd after the Barclays Premier League match between Manchester United and AFC Bournemouth at Old Trafford on May 17, 2016 in Manchester, England. (Photo by Michael Regan/Getty Images)

Wayne Rooney of Manchester United celebrates as he scores their first goal during the Barclays Premier League match between Manchester United and AFC Bournemouth at Old Trafford on May 17, 2016 in Manchester, England. (Photo by Alex Livesey/Getty Images)

Louis van Gaal was booed by a number of Manchester United fans as the under-fire manager thanked them for their "unconditional support".

A topsy-turvy campaign ended with a 3-1 win at home to Bournemouth, with Wayne Rooney, Marcus Rashford and Ashley Young scoring before Chris Smalling turned in a late Max Gradel effort.

That was too little, too late for many fans, with under-fire Van Gaal jeered by portions of the crowd when addressing the fans after the game.

"I want to thank you for the unconditional support of you," he said.

"Whenever we have played, however the things have gone on the field, you never let us down.

"Thank you for that and we want to bring the FA Cup home. You deserve it. Thank you."

Asked afterwards if he understood the booing fans, Van Gaal said: "Of course, but the expectation is very high. The fans expect a lot, these expectations are too high. We are a team in transition."

Many applauded at the end of Van Gaal's address, but Bournemouth fans goaded him with chants of "you're getting sacked in the morning".

Fresh speculation linking Chelsea manager Jose Mourinho to the Old Trafford helm emerged before the match, which took place two days after a bomb scare forced its hasty rearrangement.

Error rather than terror proved to be at the heart of the issue that saw the original match abandoned, with a private security firm having left a fake bomb inside Old Trafford following a training exercise.

United refunded all fans with tickets for Sunday's match and offered them free entry to the rearranged game, but a number stayed away as Rashford followed Monday's England call-up with a lovely goal in a win that belatedly brought the Premier League to a close.

The 18-year-old's impressive finish made it eight goals in 17 matches since making his first-team debut less than three months ago and came between a Wayne Rooney goal and another that the United captain created superbly.

The England skipper opened the scoring by ending a fine team move - his 100th Premier League goal at Old Trafford - before beautifully clipping the ball over the defence for sub Ashley Young to score late on.

The three points see United usurp Southampton in fifth and secure a place in the Europa League group stage, but whether van Gaal is still presiding over the team by then remains to be seen.

There was never any chance of the club-record 19 goals required to wrest fourth place and Champions League football from Manchester City, but not even Chris Smalling's late own goal will prevent United entering the FA Cup final against Crystal Palace in good heart.

MANCHESTER UNITED: De Gea, Valencia, Smalling, Blind, Borthwick-Jackson, Carrick, Mata (Ander Herrera, 76 mins), Lingard, Rooney, Martial (Young, 84 mins), Rashford (Depay, 79 mins).

Unused subs: Jones, Romero, Varela, Andreas Pereira.

BOURNEMOUTH: Federici, Francis, Elphick, Cook, Daniels, Ritchie, Gosling, Surman, Pugh (Gradel, 66 mins), Wilson (Grabban, 79 mins), King (Afobe, 67 mins).

Unused subs: Stanislas, O'Kane, Holmes, Jordan.

Man of the Match: Wayne Rooney

Match rating: 5/10

Belfast Telegraph