As far as defensive displays go, this was one of Inter's best this season. The nature of the celebrations in the dressing roomwere a testament to that and they also showed just how tough Atalanta are to play against.
Before the game, Antonio Conte knew that it would have been difficult to go toe to toe with Bergamo side in a possession-based game, so he turned to his defence.
This back-line now looks ever more dependable and as the end of the season is in sight, they will need to count on them even more.
The Nerazzurri are the Serie A leaders with a six-point lead over city rivals Milan with 12 games to go. Several observers, not only UK betting sites, consider them the favourites to win the Serie A title this season.
When looking at the Nerazzurri this season, one has to say they have come a long way. The partnership of Romelu Lukaku and Lautaro Martinez is an elite one.
The resurrection of Christian Eriksen and Ivan Perisic is timely and there seem to be no words for Nicolo Barella's abilities.
The team is far from perfect, but results against Serie A's big teams have been impressive and this improvement is down to the team all buying into Conte's plan.
The more they do it, the more it pays off, but they do have flaws.
The Nerazzurri are seemingly set up to play the top tier teams in Serie A, as they do not need the ball.
Whilst Conte would like them to play more (they are exhibiting signs of this), they are equally happy to absorb the pressure and they are devastating on the counter.
It is actually against the "smaller teams" who surrender possession that Inter have struggled against as it needs a new approach.
Even so, they would not be able to execute their plan if it was not for their stubborn defence.
Being out of Europe helping them in Serie A is somewhat of a myth when you look at how many games Milan and Juventus have played since Inter's exit, but there is some benefit.
The lack of travel time surrounding these games also need to be taken into account and Inter have had solid weeks on the training ground.
Conte and his staff have drilled them well and they have also been fortunate with injuries so that Alessandro Bastoni, Stefan De Vrij and Milan Skriniar have been allowed to play consistently in front of Samir Handanovic.
Conte has been adamant that he wants a specific type of players. He now has them and as previously mentioned, even the likes of Eriksen and Perisic have adapted to his way of thinking.
That means he now has a team who will constantly press and track back. This starts with the strikers who apply a "defend from the front mentality."
It is worth noting that as soon as the ball is lost, one of the strikers often applies the pressure letting the rest of the team fall back into position. Both Parma and Atalanta read this well in the last two games keeping the ball out wide and making it harder for the midfield and strikers to track but the team mentality showed how committed they are to this press.
Whilst the defence has been exceptional and performances like we saw from Milan Skriniar deserve praise, the defensive duties from the forwards, midfield and wingbacks also needs praise.
Conte's system is more complex than it looks as the midfielders play to be positioned ideally to counter and lose the ball.
The positioning of the wingbacks and the defensive midfielders, for instance, is ever-changing. The defensive midfielders often go wide in the build-up, so the wingbacks can float in.
The system is not perfect but it is improving. Handanovic has had an Indian summer of late, putting in some fantastic performances and producing some incredible saves.
His lack of ability with the ball at his feet however, creates issues and the defenders often have to come too deep to collect the ball.
Inter's build-up play starts in a pressure situation, meaning the midfield drop creates distance between them and the strikers.
There are also some problems when they must press their opponents.
Conte changes how they do this depending on the team they play. In short, this can lead to Inter struggling against teams that are more fluid (like Atalanta) as it seems that many of the pressing systems almost depend on a type of man-marking.
Conte however, keeps adapting this, and so far, it seems to be paying off.
As Inter approach the end of the season, they will certainly be hoping that now, with a six-point lead on Milan and a 10-point lead over Juventus (who have a game in hand) they can see this through.
They certainly have the offensive power to do so but as the season goes on, they look better and better at the back.
This certainly was not the case early on in the campaign but as the weeks roll on they are starting to look like a fortress that cannot be breached.