Tottenham rallied from two goals down to beat Olympiakos 4-2 in Jose Mourinho's first home match to book passage to the Champions League last 16 on Tuesday night.
Mourinho, who was hired to replace the sacked Mauricio Pochettino on Nov. 19, was overseeing his first Champions League match in charge of Spurs and found his team quickly down two goals inside of 20 minutes after Youssef El Arabi and Ruben Semedo scored for the visitors.
Mourinho's first decisive act, sending on playmaker Christian Eriksen for defensive midfielder Eric Dier after 29 minutes, changed the flow and Dele Alli's tap-in on the stroke of half-time proved crucial.
"It was a disappointing start, we know we didn't come out with any energy. They got the early goal and then got the second and it was uphill from there," Kane said.
"The goal just before half-time changed the momentum. We knew we couldn't play any worse than we did in the first half."
Serge Aurier fired Spurs in front in the 73rd minute before Kane added his second to make it 4-2 in favour of the hosts to secure the impressive comeback win and all three points.
The brace makes Kane the fastest player to ever reach 20 goals in Champions League history, reaching the mark in 24 games, two faster than Alessandro Del Piero.
Mourinho, who won the competition with Porto and Inter Milan, shook hands with each of his players and applauded the fans who applauded back, if not singing his name.
The result puts Tottenham on 10 points, securing second place in their group behind leaders Bayern Munich and ensuring passage to the round of 16.