Spurs could have moved to the summit with a victory at the Hawthorns but were held to a disappointing draw, with Dele Alli's late goal needed to cancel out Nacer Chadli's opener
But without both, Mauricio Pochettino may be scratching his head as to how his side missed the perfect chance to go top of the Premier League.
Kane’s ankle injury means he will be absent until November, but the form of Son – who became the first Asian player in history to be named Premier League Player of the Month on Friday – has meant the club have hardly missed their talisman.
But having played in Seoul and Tehran during the international break, Pochettino was forced to leave the South Korea international on the bench for the trip to West Brom. Their lack of a consistent goal threat showed.
That was not to say they did not create chances, and Ben Foster had to be inspired form, particularly in the first half, to keep the scores level. He denied Dele Alli twice when through on goal, though he saved his best for Ben Davies and Christian Eriksen as he saved first low to his left and then his right shortly before the break when it seemed both had found the respective bottom corners.
Vincent Janssen held the ball up admirably, but behind him creativity was, for the most part, lacking. Son’s introduction for the final 20 minutes threatened to be the fillip required to get them over the line, but even a man in consistent form as his was unable to conjure up a moment of magic in the final third.
At the other end, former Tottenham man Nacer Chadli looked to have won it with his own piece of composure inside the box, and though Alli secured an equaliser in the penultimate minute of normal time, scrambling to a draw away at West Brom is not the result of respective champions.
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Such a scoreline was only magnetised by events at the Etihad Stadium, as Manchester City were themselves denied from the penalty spot twice by Maarten Stekelenburg as Everton held out for a point. If Spurs are to again make a sustained challenge for the title, winning at The Hawthorns while rivals are slipping up elsewhere is a must.
Some may read into it as Tottenham maintaining their unbeaten record, but this was a let-off for City and any other side who have eyes on silverware come May.
A draw against the Baggies was the catalyst to Spurs’s season unravelling last term, and though their challenge is unlikely to fall away in a similarly dramatic fashion this time around, this could yet be a huge opportunity missed come the final reckoning.