Spurs have suffered surprise home defeats to West Ham and Newcastle so the weekend duel looks hard to call.
"It's really crazy," Vertonghen told Sky Sports News.
"I think if we'd won against Newcastle, we'd be joint second now - but we're seventh.
"It's unbelievable how we play (Manchester) City and United next. It's very hard this year. (Vincent) Kompany already said it will be the toughest league in years to finish top. We have to be at our best to finish in the top four."
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