Manchester United 0 Cardiff City 2

The campaign was brought to a close with Neil Warnock's Championship-bound side scoring in both halves.

The double from Nathaniel Mendez-Laing was a sour finale for the Reds as the fans said their goodbyes to Antonio Valencia in his last action for the club before leaving this summer and there was a wave for the crowd at the end of the match for Ander Herrera, in his tracksuit following his decision to depart.

But, on the positive side, there was also a tantalising peek into the future with Mason Greenwood getting his chance in his first-ever start for the senior team.

Greenwood's impact on the match was the one bright feature of this ending to the season at Old Trafford.

Ole Gunnar Solskjaer wanted a finish to the season to brighten Reds fans' summers as they start the build-up to the next chapter and Greenwood certainly livened up the start of the dead rubber.

The 17-year-old from Bradford would have been acutely aware that the biggest cheer pre-match came when his name was announced in the stadium seconds before kick-off.

And, as the support relished yet another Academy product making it through the ranks to a senior role, the striker didn’t disappoint. Sir Alex Ferguson, who famously and successfully rebuilt United’s youth programme and restored the ethos of Sir Matt Busby’s Babes era, was just taking his seat in the VIP area when Greenwood’s name was greeted with such enthusiasm.

And Sir Alex would, no doubt, have been impressed by Solskjaer’s choice to start his first senior game and becoming the youngest-ever United player to start a Premier League game for the Reds.

Greenwood was crowned the Jimmy Murphy Youth team Player of the Year on Thursday night and his week almost got even better after just four minutes. Diogo Dalot clipped a superb ball to meet Greenwood’s penetrating run and the teenager was ahead of the chasing pack but his effort, possibly off his shoulder, looped over the bar. It would have been a dream start.

But the disappointment didn’t halt Greenwood. On top of chasing back to block an effort from Mendez-Laing as the Cardiff player was set to pull the trigger on a shot, he was also close to a debut goal again after 12 minutes. Andreas Pereira picked Greenwood out but again his headed chance wasn’t converted, as Neil Etheridge dived to flip it to safety.

A Greenwood goal would have stolen Marcus Rashford’s record as the youngest United player to score in the Premier League and the Mancunian was also prominent as United searched for a lead. He had two efforts in the space of a couple of minutes but couldn’t find the target.

Despite being in command, United slipped behind to a controversial goal.

Referee Jonathan Moss judged that Dalot had brought down Mendez-Laing after 23 minutes. TV replays showed that the striker had swiped and missed his shot and started to fall before the Portuguese full back made contact. Arguments from the Reds camp came to nothing and Mendez-Laing stroked home the spot-kick to make it 1-0.

Greenwood it was again with almost an immediate response but this time his shot was deflected and and Etheridge then got down to nudge the ball off a post and out for a corner, just as it looked like it might squirm home. After 38 minutes, he was once again in a good position to strike but chose a left-footed shot that hit the side-netting.

United couldn’t find the goal to hit back and Cardiff almost went further ahead just before half time but David De Gea pulled off a great save to deny Josh Murphy.

Solskjaer brought on Anthony Martial at half-time for Phil Jones but, before the French winger could get his teeth into the match, United went 2-0 down.

A simple move down United’s left saw Murphy stride into space and square the ball and it just eluded a rescue attempt from Dalot, for Mendez-Laing to sidefoot home his second from close range.

United were shocked into action and Rashford had a header saved by Etheridge and Martial was also denied by the Cardiff keeper.

The hosts, though, were struggling to find rhythm or a meaningful answer to the stunning scoreline and the Bluebirds almost made it worse when a quick break from Etheridge’s punt upfield found Bobby Reid stealing in behind United’s rearguard but he lashed his shot wide.

There was a double substitution for United in the 73rd minute that illustrated the past and future nature of this final match of the campaign when Valencia came on for a farewell cameo and Angel Gomes was also thrust into the action.

Old Trafford was willing Greenwood to get on the scoresheet to at least bring the curtain down on the campaign on a positive note but he just couldn't connect with Rashford's low cross in the 87th minute. In front of the Stretford End, it would have been a great ending for the teenager's big day.

But it just wasn't to be on a forgettable last match of the season for United as Rashford and Lingard were also unable to convert late openings.

United: De Gea, Dalot (Valencia 73), Smalling, Jones (Martial 45), Young (C), Andreas (Gomes 73), McTominay, Pogba, Lingard, Rashford, Greenwood.

Subs not used: Romero, Fred, Garner, Mata

Bookings: Andreas, Pogba, Lingard

Cardiff City: Etheridge, Peltier, Bennett, Morrison (C), Ecuele Manga, Zohore (Ward,73), J. Murphy, Reid, Bacuna, Gunnarson (Richards 58), Mendez-Laing.

Subs not used: B. Murphy, Cunningham, Harris, Healey, Hoilett

Goals: Mendez-Laing 23 (pen), 54

Bookings: Bacuna, Murphy, Morrison

Attendance: 74,487