LONDON • What is wrong with Dele Alli? It is a question that has been nagging away at many Tottenham fans for much of the season, although it has yet to be asked by the two managers guiding his career, at least not in those terms.

Before the 2-0 win over Brighton & Hove Albion last Wednesday, when he came off the substitutes' bench, having been unable to train because of illness, Alli had started in all but one of Spurs' games for which he had been available this season. He also remains fundamental to Gareth Southgate's plans for next summer's World Cup.

The view at close quarters from Spurs manager Mauricio Pochettino is that Alli's attitude and commitment is the same as it has always been since his first season at the club two-and-a-half years ago, but that his confidence levels have dipped as his goals and match-winning contributions have dried up.

Alli has not scored in nine games since his brace helped earn Tottenham a Champions League win over holders Real Madrid at Wembley on Nov 1, with his most recent Premier League goal coming 10 days earlier in the 4-1 win over Liverpool.

Pochettino defended Alli on Thursday, arguing that he is being victimised for overachieving in the past.

But others at Tottenham would privately concede that some aspects of his performances have not changed. They feel in previous seasons that his goals helped to mask other deficiencies, such as his tendency to give the ball away and his habit of lunging into tackles.

The statistics support this view, and in terms of chances created and involvement in goals, Alli's numbers for this season are very similar to those from last year, although there has been a striking drop in the number of shots he has had on target.

Put simply, the 21-year-old appears to have mislaid his shooting boots.

"His success in two-and-a-half years is massive, a fantastic achievement," Pochettino said.

"It's not that he isn't doing good - the problem is that in the past he was amazing. Sometimes to be consistent, a player needs to go down to come back up."

England's coaching staff have a similar perspective, because despite the faith shown in Alli by Roy Hodgson, Sam Allardyce and Southgate, he has rarely controlled games for his country.

His real value is to be found in a series of momentary yet significant contributions.

Alli is seen as more of a Frank Lampard-type player; a goalscorer rather than a dominant figure.

Those close to Alli in the Tottenham dressing room attest to the profound impact the perceived dip in form has had on a normally lively character, who has taken some of the criticism from the likes of Alan Shearer to heart.

Harry Kane went through a similar tricky spell at the start of his second season in Spurs' first-team squad when he did not score until the end of September.

As with his team-mate, Alli has struggled to adapt to the transition from being lionised to criticised for the first time in his career.

Pochettino's response has been to continue to pick him both as a show of faith and in the hope that he will play his way into form.

It is an approach that is set to continue throughout the Christmas period when Tottenham have a series of winnable games against Burnley, Southampton, Swansea and West Ham.

The Argentinian's main concern is that opponents are seeking to provoke Alli, who is deemed to have a short fuse and potential temperamental weakness.

Manchester United and Manchester City players have appeared to try to get under his skin this season.

Pochettino is hoping that one goal will trigger an avalanche, as happened about this time last year when Alli scored six goals in three matches from Dec 28, kick-starting a period that resulted in him scoring 14 league goals after Christmas as opposed to four before.

THE TIMES, LONDON