Son has shone twice since Tottenham unveiled its new stadium. The South Korean striker scored the first ever goal in the new arena when he netted against Crystal Palace on 3 April in the 2-0 win in the Premier League.
Six days later, he was at it again. His goal in the second-half followed Hugo Lloris's heroics in the Tottenham goal during the first period.
The World Cup winning France international has come under fierce criticism for a spate of flaky performances. But he was at his impenetrable best on Tuesday night. He flung himself to his left to parry away Sergio Aguero's 13th minute penalty and was solid throughout the game.
Following the victory, the Spurs boss, Mauricio Pochettino, challenged his players to maintain the spirit that led to the triumph.
"The penalty save gave us a big lift," said Pochettino. "The energy was good. There were still 90 minutes to play and it's Manchester City. But with the spirit we play, anything is possible."
Spurs might have to play the second leg on 17 April without their star striker Harry Kane who injured his left ankle in a tackle on Fabian Delph early in the second half.
"It is very sad and very disappointing," added Pochettino. "It is a worry for us. We hope it is not a big issue. But there is not too much time to recover."
Having won the League Cup, reached the FA Cup final and in the driving seat for the Premier League title, City were unable to match the intensity of their hosts.
"Nobody said the match would be easy," added City boss Pep Guariola. "It was a good performance but we lost ... but that's the Champions League. We have the second game and we will see what happens."