Kane faces possible career-changing game vs. Ronaldo and Real Madrid
MADRID, Spain -- Remember when Harry Kane had to prove to the world that he was not a one-season wonder?
It wasn't that long ago but, having scored 21 Premier League goals for Tottenham in his first full season at the top level in 2014-15, Kane responded to his doubters with 25 league goals the next season and 29 the year after.
He has six in eight games so far for Spurs in the Premier League this season, so it is safe to suggest that the 24-year-old has silenced even his most ardent critics. Nobody now questions whether Kane is the real deal. But it seems there is always another challenge for the current England captain, another mark that he must pass, before being bestowed with the true mark of greatness.
And the next box waiting to be ticked comes this week, with Kane and Spurs facing perhaps the toughest challenge of them all with a Champions League group stage clash against Real Madrid in the Santiago Bernabeu on Tuesday.
For Spurs collectively, Mauricio Pochettino's young team will be measured against the reigning European champions in their own intimidating fortress. But Kane will also inevitably find himself judged against the goal scoring feats of Cristiano Ronaldo and on how well he performs on the biggest stage of club football.
There will also be the Gareth Bale subplot -- the Wales winger is fighting a losing battle against a calf injury to be fit to face his former club -- and the speculation surrounding whether Kane has what it takes to follow his old Spurs teammate to Madrid.
Not that anyone is suggesting that Kane will be putting himself in the shop window on Tuesday night. The man himself has made no noises whatsoever about moving away from Tottenham and the club will resist any offer for their talisman, but it would be naive to think that Real's scouts will not be watching Kane closely when he's playing in their stadium.
Identifying, and then signing, the world's best players is what Real do and Spurs have had recent experience of their ability to get whoever they want having seen Bale and Luka Modric lured to the Bernabeu from White Hart Lane.
On Tuesday, Kane will be just 34 days older than Bale was when he left Spurs for Real in 2013 for a world record €100 million, so it is legitimate to compare the two players in terms of status and development at the same age.
Kane is now unquestionably the star name in English football and Tottenham's leading light; Bale held a similar position in 2013, albeit as Wales's top player rather than England's, but the winger held one crucial edge over Kane by virtue of his Champions League record.
Bale's hat trick in Tottenham's 4-3 win against Inter Milan in October 2010 saw him announce himself to the world on the European stage and he has not looked back since. Those performances during the 2010-11 Champions League campaign caught Real's attention and if Kane can replicate that in any way then he can move himself to an even higher plane than he occupies now.
Scoring a hat trick against Cypriot outsiders Apoel Nicosia is one thing, but doing it against the very best is a different matter altogether -- that is the door that Kane now has to walk through if he is to join the likes of Bale just beneath Cristiano Ronaldo and Lionel Messi in the Champions League hierarchy.
Maybe he can climb even higher and rub shoulders with Ronaldo and Messi, but the comparisons with those two -- and there have been some -- are premature and overlook the reality that Kane remains a relative novice at the highest level.
His lack of experience in the Champions League ensures that Tuesday's trip to the Bernabeu will be his first. Kane has also not played against the likes of Barcelona, Bayern Munich and Juventus, so it is clear that he still has something to prove against Europe's elite.
But Kane has a track record of overcoming all the challenges placed before him, and in spectacular style. The "one-season wonder" now has 84 goals in 124 Premier League appearances for Spurs, he has scored 12 goals in 23 games for England and, in the Champions League, he has already bettered his return of two goals in three games last season by hitting five in two outings already this term.
He is an established Premier League superstar, but that status has still to be earned in the Champions League. It is against heavyweights such as Real Madrid, that Kane can smash through another ceiling.
If he can walk off the Bernabeu pitch having gone toe-to-toe with Ronaldo, in terms of influence on his team and goal scoring contribution, it will be a career-changing performance. Kane has that potential in his locker but he will send his career into the stratosphere if he delivers in Madrid on Tuesday.
Mark Ogden is a senior football writer for ESPN FC. Follow him @MarkOgden_