Chelsea may have needed the "wake-up call" of losing to Burnley last week to show them the level of effort required to defend their Premier League title, says goalkeeper Thibaut Courtois.
The 25-year-old admits Antonio Conte's side "started bad" with defeat at home on the opening weekend of the season.
They responded with Sunday's 2-1 victory over Tottenham.
"We don't have the easiest start but this victory is good for the confidence," he said.
"Maybe we needed as a group a little wake-up call and say 'look, we need to give 150% this year and not 100%'."
Marcos Alonso scored both of Chelsea's goals at Wembley, the second of which came in the 88th minute.
Captain Gary Cahill and midfielder Cesc Fabregas missed the game through suspension after being sent off in the 3-2 loss to Burnley, while Eden Hazard is still out through injury.
"Physically we dug very deep," said Courtois. "Spurs, especially the last 15, 20 minutes of the first half, they had a lot of pressure on us. As well in the second half.
"You see that physically we are very good and for us that is important."
Spurs have now lost seven of their past 10 games at Wembley.