Ralls saw red for a cynical lunge on Lucas Moura on the hour mark.
Kane also saw a yellow card for his reaction to Ralls, but Warnock was scathing of how the Spurs players surrounded referee Mike Dean, who initially seemed set to show just a yellow card.
“It didn’t help being surrounded by 15 white shirts,” said Warnock.
“He (Kane) is doing that to make an issue of it. An England player going off like that… then he’s grabbed him, why not give him a red card?
“I don’t think he needs to do that, he’s a tremendous player. I love him playing for England. Just because he’s had a poor game and Spurs are having a poor game, don’t take it out on us.”
Outclassed by the brilliance of Barcelona’s Lionel Messi in the Champions League in midweek, Spurs were grateful for Cardiff’s lack of firepower to ensure a lacklustre performance after Eric Dier’s early opener went unpunished.
Toby Alderweireld cleared off the line from Josh Murphy and Hugo Lloris was forced into a fine save from Sean Morrison as Spurs failed to add to their advantage despite Ralls’s dismissal.
“It wasn’t the best performance,” admitted Spurs boss Mauricio Pochettino. “We are in a very good position in the table, one point to the top, but if we want to be in the same positon, or be a contender we have to improve a lot the performance.”
Despite a World Cup hangover with a spate of muscle injuries and the uncertainty over when the club’s new stadium will be completed, a return of six wins from their opening eight Premier League games matches Spurs’ best ever start to a campaign under Pochettino.
The disruption in relocating the match to Wembley due to delays in completing the new White Hart Lane did though lead to a sparse crowd on a sodden day in the English capital that surprised Pochettino.
“I was a little bit surprised,” said the Argentine. “I understand, we cannot ask for more of our fans. It was a difficult day, the weather and everything, the last tier was empty.”
– Dier delivers –
By contrast to their domestic form, Dier was one of three changes from a second straight Champions League defeat that leaves Pochettino’s men staring down the barrel of an early European exit.
And he made an almost instant impact with his first goal since April 2017, slamming home an easy finish from close range on eight minutes after Davinson Sanchez’s blocked header fell kindly into his path.
Spurs, though, failed to build on that positive start and gave a Cardiff side still looking for their first win back in the top flight plenty of encouragement.
Lloris was badly at fault for Barca’s opening goal on Wednesday as he rushed from his line and was caught in no man’s land as Philippe Coutinho stroked home.
And that seemed to be playing on the France captain’s mind as he didn’t come to collect a through ball and had to be bailed out by Alderweireld’s brave clearance after Murphy flicked the ball goalwards.
Kane had bounced back to form with four goals in his last three games, but the England captain was kept largely quiet.
Cardiff goalkeeper Neil Etheridge produced a good save to parry Kane’s header early in the second half before Lucas’s follow-up effort was brilliantly cleared off the line by Morrison.
And despite Ralls’s dismissal, Cardiff could still have levelled when Morrison’s header was turned onto the post by Lloris and Alderweireld was again on hand to hack clear the danger.
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