Dele Alli is untouchable at Tottenham and helped Spurs destroy Manchester United… but he has to start turning up more, even if he is only 21

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Dele Alli was taken off in the 88th minute against Manchester United but it was what he did in the 85th that earned the England youngster a standing ovation.

The 21-year-old gave Alexis Sanchez a kicking and was rightly shown a yellow by referee Andre Marriner. The Tottenham crowd, who had booed every touch of the ex-Arsenal man, loved it.

Yet that was not all the attacker did at Wembley Stadium. Indeed this was one of those games where Alli was in the mood, just like he was against Real Madrid in November.

Dele Alli (left) thrilled Tottenham fans by kicking Alexis Sanchez (right) late in the game

Alli has put in commanding performances this season but mostly in the big games

He assisted Christian Eriksen's opener after 11 seconds, nutmegged Sanchez in the build-up to Phil Jones' own goal and should have been awarded a penalty after Antonio Valencia's clumsy challenge. Were it not for Alli, the scoreline could have been very different.

The trouble is, this has become a rarity from the Spurs starlet. Like in the 3-1 Champions League win over Real at Wembley, he rose to the occasion.

Alli could not help himself with that kick on Sanchez's ankles – a sign of his occasional petulance – but this was one of his finer performances overall.

With Tottenham's abysmal away record against the big six, Pochettino will hope he turns up against Liverpool on Sunday too.

His reputation may have gone against him in the decision not to award a penalty 

In the 4-1 win over Jurgen Klopp's side in October, Alli scored one of his five Premier League goals this season. By the start of February last season, he had 11.

We all know he is only 21 and, of course, someone of that age is allowed dips in form. Yet when you have been touted as the next Galactico and worth £100million, there has to be a greater consistency.

There have been signs of frustration this season, such as his lunges on Manchester City's Kevin De Bruyne or Burnley's Charlie Taylor, both of which saw him escape red. There have been diving issues too – and that reputation may not have helped when Valencia wiped him out on Wednesday.

If Spurs are to secure a Champions League spot, then they need their young gun to start firing again. Harry Kane is playing his part, so too is Son Heung-min, and Christian Eriksen makes Tottenham tick.

Alli had scored 11 goals in the league by this time last season but has only five this campaign

Alli hasn't been – not as much as in the last two seasons anyway. In 2017-18 he is averaging a goal or assist every 168 minutes, compared to 122 in 2016-17 and 130 in 2015-16.

Eriksen is currently far more indispensable for Tottenham. The Dane has scored seven and assisted six, and while out with illness his team drew 1-1 with Southampton then League Two Newport.

Alli has to start showing why he too is vital with Gareth Southgate keeping a close eye. When it comes to England, the No 10 position for the 2018 World Cup is still up for debate.

Jesse Lingard is enjoying his best season to date while Raheem Sterling is a key part of a team that is making a mockery of the Premier League's reputation as the toughest in the world.

Christian Eriksen has become a far more important player for Tottenham than Alli 

Speaking this week, Glenn Hoddle said he does not think Alli will be worried.

'He's had a slightly indifferent season but he's still affected the game,' Hoddle said. 'He will affect the game as he's a box threat and he likes to score goals.

'He's done that time and time again over the last few seasons and we forget how young he is. It's great seeing two young English players (him and Lingard) playing well in that position.'

It is now more than two years since Alli scored that volley against Crystal Palace at the age of 19. Now 21, he cannot rely on only offering moments of magic every so often. Consistency is needed, for Tottenham and England.