The North Londoners put their opening day defeat against Everton behind them as Harry Kane and Heung-Min Son’s masterclass romped Mourinho’s men to a comfortable victory.
The hosts drew first blood through their familiar source Danny Ings on the 32nd minute mark but Tottenham replied with four goals in 28 minutes.
There was still time for Kane to get on the scoresheet himself when he turned in the rebound after Erik Lamela struck the post.
Speaking to the media after the game, Mourinho hailed Kane for his stellar performance and insists Spurs were too good for the Saints after the break.
“We didn’t start bad at all. In the first 10 or 15 minutes we were good. After that we lost control,” he said.
"In the centre of our defensive area, we were a bit sloppy. We lost some duels. They got the ball behind us too easy. I was on the bench and thinking I would be happy to get in at 1-0.
“The goal gave us a different position in the game. In the second half, Harry Kane killed the game, the way he connected the game, the way he was dropping, he allowed Son Heung-min into attacking spaces. His performance was amazing.
“In the second half we were too good for them
“We know Southampton quite well - we played them four times last season, twice in the league and twice in the cup.”
“[Former Southampton midfielder Pierre-Emile] Hojbjerg helped us to analyse and understand the way they play. We knew they risk a lot.”
"The full-backs leave a lot of space behind. By Harry Kane’s movement we killed them. He changed the game for me and of course Sonny.”
