Thibaut Courtois believes Chelsea needed the "wake-up call" of losing to Burnley to show them the effort that is required to retain their Premier League title.
Antonio Conte's side recovered from that shock opening weekend defeat to beat London rivals Tottenham 2-1 at Wembley on Sunday.
Marcos Alonso struck twice to seal three points for Chelsea, despite the fact Spurs dominated for long periods and levelled courtesy of a Michy Batshuayi own goal.
Chelsea had captain Gary Cahill and Cesc Fabregas suspended after their red cards against Burnley, while Eden Hazard is still missing through injury.
Conte altered his tactics as the visitors operated with a five-man midfield which soaked up plenty of Spurs pressure before Alonso hit a soft 88th-minute winner, and Courtois feels the victory came after an eye-opening afternoon against Burnley.
"We just started bad," he said.
"Maybe we needed as a group a little wake-up call and say 'look, we need to give 150 per cent this year and not 100 per cent'.
"That's what we did (against Spurs), I think we did very well. You see that in the end. We can win those difficult games. I remember two years ago we had to go to Man City and lost there, and it was a difficult start for us.
"Now, this victory is good. Next week we play at home against Everton, who are doing well. We don't have the easiest start but this victory is good for the confidence, to continue the hard work we are doing in training.
"Physically we dug very deep. 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. Even if you see Marcos in the end, he was very tired, but still he made that run to score. You see that physically we are very good and for us that is important."
Courtois now wants to use the win as a starting point to mount a serious defence of their Premier League title.
"I think we are doing very well, I think we worked very hard in pre-season, it was just a bit unfortunate that we had suspended and injured players, some players left, so it's not easy for us in pre-season," he added.
"I think this victory is good to show as a team we are working very well and in the next weeks we can continue in this way, we are working very hard in training and that shows that the work pays off.
"For the group this week we train very, very hard, that shows off today. That's a pleasure for us and for the manager."
Spurs bossed large periods of the game with no reward to show for it - Harry Kane hitting the post the closest they came to scoring for themselves.
They have now lost seven of their last 10 games at Wembley, although manager Mauricio Pochettino insisted before and after the game that playing in unfamiliar surroundings is not an excuse for such a poor record.
Kane acknowledged the lack of cutting edge in front of goal as the main issue but said his record of never scoring a Premier League goal in August is not on his mind.
"It is not the result we wanted but we can take a lot of positives from the way that we played," he said.
"We dominated the game and had the better chances first and second half. It is about being clinical. We have to hold our heads high.
"We played a good game. It was not our day today we have to move on and try and win next week.
"It (not having a league goal in the month of August) is something that is spoken about a lot but I am not too bothered by it.
"I try to play well for the team and play well every game. Sometimes the ball does not go in as it did today off the post and the few chances I had.
"It is part of the game, I just need to keep working hard, keep my head down and I am sure the goals will come."