Son was the matchwinner as Spurs defeated Manchester City in the first-leg of their Champions League quarterfinal this week.
And Vertonghen has called on the South Korean and his team-mates to step up again to complete a famous victory and cement Tottenham's place in the Premier League's top four.
“Everyone is counting on Sonny," he said. “We'll have Harry coming back from injury hopefully soon. Everyone needs to step up like we did before.
"We won I think all of our Premier League games without Harry and hopefully we can do it again."