It's incredible to think that Harry Kane was once labelled a 'one-season wonder' at Tottenham.

The 2014/15 campaign was when the 24-year-old announced himself in the Premier League with 21 goals in 34 games - five behind Golden Boot winner Sergio Aguero.

At the season's end, football fans were quick to write off Kane and said he wouldn't be able to keep up his goalscoring heroics.

And yet, here we are in 2017 and Kane has two Golden Boots to his name, having scored 25 and 29 league goals respectively in the past two seasons.

There is even speculation of the England international breaking Alan Shearer's Premier League record of 260 goals.

Kane currently has 84 to his name, but if he stays at Tottenham his whole career and keeps bagging 25 per season, who's to say he can't?

That remains to be seen, so for now the looming question regarding Kane is: can he be called world class yet?

Some say yes, some say no, but his recent Ballon d'Or nomination suggests he's close.

However, one person who believes Kane is NOT world class yet is Jamie Carragher, who writing for the Telegraph has perfectly explained what the striker is missing to join that bracket.

Take it away, Carra.

"It is often said in football the word 'legend' is applied too loosely," Carragher wrote. "The same must be said of the phrase 'world class'.

"Too many players are given this tag, but we should pause before handing out such lavish compliments.

"That is why I do not agree with those arguing Harry Kane is a world-class footballer. He isn't. Not yet.

"My criteria for world-class status are stricter than excelling in the Premier League, no matter how long Kane terrorises defences domestically.

"World-class players are those who deliver in the post-Christmas stage of the Champions League, shining in the quarter-finals and beyond.

"World-class players are those who deliver at major international tournaments.

"By the end of this season Kane might tick both boxes. He has the credentials, but until such time becoming English football's most talented footballer is not enough."

Nailed it. Kane is a phenomenal talent, but big games in the Champions League and World Cup are where world-class players are really made.

Only until the 24-year-old delivers in that kind of environment can he be called world class, like how Cristiano Ronaldo, Lionel Messi and Neymar do every season.

It's surely only a matter of time before Kane does realise that potential, though.