Son Heung-min admitted he was left feeling "very sad" after Tottenham were thrashed thrashed 4-1 by Leicester.
And it was also a nightmare debut for Spurs new boy Pedro Porro, who was branded "unbelievably bad" by former Tottenham boss Tim Sherwood on Saturday afternoon.
Antonio Conte returned to the touchline for the trip to the King Power Stadium, which came less than a week after he had missed the priceless 1-0 win over Manchester City after undergoing surgery.
But after a bright start, which included Rodrigo Bentacur nudging the visitors into an early lead, Tottenham unravelled against Brendan Rodger's side, who surged to victory courtesy of goals from Nampalys Mendy, James Maddison, Kelechi Iheanacho and Harvey Barnes.
A dejected Son pulled no punches with his assessment after the final whistle, and he stressed that Tottenham needed to learn from their mistakes. Speaking to Match of the Day, the forward said: “We started quite well and created chances. After it was 1-1 we conceded a quick second goal and then it was open. It was a difficult game then. Leicester were so clinical, they almost scored every chance. It’s a very disappointing result.
“I think it’s very sad. We knew it was going to be a really hard game. In the Premier League it’s never an easy game. It showed the Premier League has a high level. I don’t know what I can say, it’s very disappointing.
"I don’t think [it was complacency]. We came with a good feeling after beating City. The first minute we were really on it. We should be ready and learn something. Today should be a big lesson for us."
There were plenty of harsh lessons for Spurs debutant Porro, who struggled to live up to expectations on his first appearance for the club since arriving in a £40million deal from Sporting Lisbon.
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The Spanish international endured a torrid afternoon up against Barnes and was taken off shortly before the Leicester winger had bagged the hosts' fourth goal of the afternoon. And he was absolutely savaged by former Spurs chief Sherwood, who was analysing the game for Sky Sports.
After criticising the right-back earlier in the match, Sherwood said after Leicester's third goal: “I don’t want to keep picking on the kid but he [Porro] needs to be relieved of his duties at the moment.
“I’m giving him the benefit of the doubt because it’s his debut but Pedro Porro is so bad it’s unbelievable. His positioning is disgusting, Barnes and Maddison are destroying him down the left hand side.
“He’s just ran inside him, he hasn’t even seen him, he gets the ball played in and lets him run inside him.”
