The Chelsea that I saw earn a dramatic 2-1 victory against Tottenham at Wembley was not the Chelsea that I usually see, and not the Chelsea that I saw so often on their way to winning the title last season.
This was a Chelsea that employed a 'catenaccio' tactical system - a counter-attacking style which became popular in Italian football where teams dig deep, hope for one or two chances to score, take them and then close the game down again.
It worked perfectly against Tottenham as Marcos Alonso converted both of their shots on target.
Chelsea's Italian manager Antonio Conte was forced into playing catenaccio because of the Blues' problems with personnel.
Their title win last season was spearheaded by the attacking trio of Diego Costa, Eden Hazard and Pedro - but with Costa's situation still unresolved, Hazard out injured and Pedro only fit enough for the bench, Conte had to do something different.
I'm not sure this is a tactic Chelsea will employ regularly over the rest of the season.
But they just didn't have the personnel to play in a more attacking way against Spurs, so they said they would do it this way and ended up getting the result they wanted against the team who were their nearest challengers last season.
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Moving Luiz into a three-man midfield paid off
You could see from the moment the Chelsea team was announced what Conte was trying to do.
He decided to play 3-5-2 with Alvaro Morata up top and Willian just behind, as opposed to the 3-4-3 formation they usually play, and he used centre-back David Luiz as a holding midfielder.
N'Golo Kante and Tiemoue Bakayoko - who was making his debut after signing from Monaco this summer - were in alongside him, meaning they were playing with three defensively minded players in central midfield.
Every time Tottenham's Dele Alli tried to go into those areas in the hole just behind striker Harry Kane, Luiz was almost always there. And if he wasn't, then Kante was there. Or Bakayoko was there.
Chelsea changed to a three to keep the middle solid and not let anything through there. Alli did nothing and Christian Eriksen also had a difficult time because there were too many bodies to get through.
That forced Tottenham out wide and Chelsea defended well from all the crosses.
Spurs produced 23 of them from open play, but only two were successful in finding a home shirt. That's because Chelsea had enough bodies to cope and head them away because of their organisation and discipline - which all came from the way Conte set his team up.
Spurs didn't have the patience or guile to break them down
When I played in AC Milan's dominant team of the late 1980s and early 1990s, most opponents played like that against us because we were a successful side who had lots of attacking talent.
It is difficult because you can't get through and they just wait for you. You need to be patient.
Spurs had difficulty in finding holes. They had one moment in the first half when Harry Kane hit the post but for the rest there was not much danger for Chelsea.
Tottenham needed luck and they got it when the goal finally came through Michy Batshuayi's own goal.
Spurs had 68% possession over the 90 minutes but they still couldn't create a lot. They couldn't find a solution to get through Chelsea.
So how should they have done it? You have to open them up by stretching them by making runs.
If Kane makes runs behind the Chelsea wing-backs then they go back and the Spurs full-backs are free. If you make runs you have a chance of breaking them down.
Morata can replace Costa - but not in a game like this
There was a lot of hype around this game as the biggest of the early Premier League season, but I didn't find it an interesting match to watch.
That's because Chelsea played a lot of long balls as soon as possible to Alvaro Morata, hoping he could hold the ball and from there score a goal.
Chelsea only had 32% of the possession and a passing accuracy of just 69% - their second lowest under Conte.
A game like this is not for Morata.
The Spain striker is a fantastic player when the ball is played into the box, but he is not a counter-attacking player. He is a player who loves to play around the box - that's what he did for Juventus and that's what he did for Real Madrid.
He is not a player who will receive long balls, hold it up and keep it for you. He is a link player, a clever player, but he needs people around him to get the service.
Chelsea only provided that on a couple of occasions and both times he nearly scored. The first - a free header from six yards when he was picked out by Cesar Azpilicueta - should have been a goal. It was a huge miss for him.
If Chelsea play a more attacking system then he can be the man to replace Costa, whose future is still unclear. He is not the same kind of player as Costa who, as we know, is a more physical kind of striker.
But they need to use Morata in a way which suits his qualities. On Sunday it was too difficult for him.
Chelsea must find a solution to Costa situation
One of Chelsea's biggest priorities before the transfer window closes on 31 August is finding a solution to the Costa situation. It is a bad thing for both parties.
We hear Costa is off training somewhere in Brazil - that is no good for him, for the club or for anyone. Somebody from Chelsea needs to go to Brazil, apologise and see if he'll come back.
If he won't return then you have to find the best solution for the club. But this was a mistake by Conte, and I hope he learns from it.
Really, the only solution now is that Conte and Costa meet face to face. Of course, you don't have to like each other, but you do need to respect each other. If Costa wants to leave because he says he feels humiliated, I wouldn't be surprised by that.
I'm not in the locker room so I don't know what exactly is happening there. Maybe he provokes all sorts and says he wants to leave, or maybe there is just not a good understanding between him and Conte. There are a lots of things that could be happening.
But to send him a text telling him to move is strange. Something happened that led to the decision that he had to leave Chelsea.
In terms of new signings, I think they need more depth in midfield and maybe also up front. They need an attacking midfielder because they already have Kante, who is defensive, and Bakayoko, who is a bit of both. They need a little bit more creativity.
Ruud Gullit was speaking to BBC Sport's Jonathan Jurejko.