Although only time will tell how good a transfer window Barcelona had this summer, all indications point to it being one that both set them up nicely for this season and has a big influence on the club’s future.

This is the first summer window in which the club has been allowed to register players since 2014 because of a FIFA-imposed transfer ban.

In the window last year, they signed Arda Turan and Aleix Vidal, but neither was allowed to feature until January.

Whereas Barcelona brought in players who were ready to perform immediately in the summer of 2014, such as Ivan Rakitic, Luis Suarez and Jeremy Mathieu, the focus this year has been on younger stars.

In one fell swoop, the club acquired excellent back-up for the stars they already have and also laid the foundations for deep changes in the years ahead.

They added a total of six new players to the squad, as well as promoting Sergi Samper to the first team before loaning him to Granada.

The first deal over the line was bringing Denis Suarez back from Villarreal. The Catalans paid €3.25 million for him, according to their official website, exercising the buy-back fee they had on him. 

During his time in Andalusia on loan with Sevilla and then on the east coast with the Yellow Submarine, Denis improved radically. Getting minutes at a high level boosted both his game and also his confidence. He ended up playing a key part in Villarreal’s run to last season's Europa League semi-final, displaying the technique, passing range and intelligence that is demanded from a Barcelona midfielder.

He is 22, and there are still a few years ahead before we find out just how good he can be, but bringing him back in was a no-brainer. As well as the interior positions, he can also cover for Neymar on the left wing.

Next through the door was Samuel Umtiti, the centre-back brought in from Olympique Lyonnais. He cost Barcelona €25 million. 

Umtiti has taken to playing for Barcelona like a duck to water, with manager Luis Enrique even picking him over Javier Mascherano for the tough away trip against Athletic Bilbao, despite the Argentinian having recovered from his hamstring injury. 

To play as a centre-back at Barcelona, you need to be able to play high up the pitch and be both strong and also good with your feet, bringing the ball out from the back.

Umtiti, 22, has shown he fits the bill despite his tender age. His transfer fee was far from exorbitant for someone who racked up well over 150 games in France, including some in the Champions League and Europa League.

He is a proactive defender who seeks and destroys instead of standing off and pondering. As we have seen from his first few performances for Barca, Umtiti has no qualms about dribbling around opponents, either.

Lucas Digne was another addition from Ligue 1. The former Paris Saint-Germain full-back—who was on loan at AS Roma last season—signed for an initial €16.5 million. 

He has perhaps been the acquisition who has most surprised Barcelona fans. The Mirror's David Anderson reported Roma were unable to stump up the cash to make his switch to the Italian capital permanent and Liverpool had been caught in two minds over whether to sign him before the Catalans struck.

Having cleared Adriano off the books, an understudy to Jordi Alba was required. And most thought Digne would be here to play that role. However, his good performances thus far indicates he could challenge the Spaniard for his spot in the team.

Digne has been solid at the back and, with each game, is getting better going forward, although matching Alba’s capacity to bomb on will be tricky. He is one to watch as the season progresses.

Following the full-back's arrival came the most surprising move of Barcelona’s summer, when they pounced for Andre Gomes as Real Madrid balked at Valencia’s asking price, per Carlos Carpio in Marca.

They shelled out €35 million for Gomes, with a potential €20 million more going to Los Che in add-ons based on how player and team alike perform during his stay in Catalonia, per Barca's official site.

Signing him from under the noses of their archrivals is just one of the benefits of his arrival. Gomes, who recently turned 23, could be the long-term replacement for Andres Iniesta, 32.

Denis is another bet for this position, because replacing the veteran playmaker is not something Barcelona can take chances with.

Of course, Iniesta is still playing marvellously, and the transition will not happen this season, although Gomes will be useful when Enrique wants to rest his captain. 

Adding Gomes to the squad also helped the coach move Sergi Roberto to right-back permanently, confident there will be enough cover in midfield for the Catalan midfielder to stay in his new position.

Netherlands goalkeeper Jasper Cillessen was next in, filling the gap left by the departure of Claudio Bravo. He cost an initial €13 million, while the club raked in £15.4 million for the Chilean, with the potential of £1.7 million more in add-ons, according to the Blaugrana (h/t BBC Sport).

Letting Bravo go eases the pressure that was building between him and German stopper Marc-Andre ter Stegen, with the latter now set to take over as the first-choice stopper in all competitions, bar the Copa del Rey most likely. 

Cillessen, 27, is a fine goalkeeper to have as a back-up and jumped at the chance to join the Catalan giants. While fans might not see much of him, they can rest assured he will be ready as and when he's needed. 

Finally, they landed Paco Alcacer on Tuesday, the player's 23rd birthday, for €30 million. This was the fourth striker Enrique had been hunting for all summer.

As explained in a previous article, Alcacer gives Barcelona a first option on the bench instead of a last resort. He may find it hard to start many games with Lionel Messi, Suarez and Neymar at the club, so when he gets chances, he has to take them.

Alcacer gives Barcelona extra goal power for when the South American trident can’t find a way through, and his presence also gives the coach the chance to rest his Uruguayan hitman. While Denis, Turan and Rafinha are options in the wider positions, beyond Suarez, Barcelona had no reliable No. 9.

Munir El Haddadi went on loan to Valencia the same day, and this is the piece of business Barcelona fans are least happy with.

Los Che have an option to buy Munir for €12 million, and Barcelona have no clause that allows them to buy him back in the future, per Tomas Andreu of Sport. 

Supporters who believe in Munir would have liked to have seen such a condition included—similar to the one that saw Denis return this summer.

Beyond that, most have been happy with the club’s sales. They have cleared millions off the wage bill by letting Alex Song, Bravo, Marc Bartra, Thomas Vermaelen and Dani Alves go.

Bartra's departure was a sad sight for the fans who had hoped he would be the next Masia player to make the grade, but it became evident that Lucho did not fancy him.

Sandro Ramirez joined Malaga on a free transfer, while Martin Montoya did the same to sign for Valencia. Cristian Tello and Douglas were also shifted, on loan to Fiorentina and Sporting Gijon, respectively. 

Alen Halilovic was also allowed to leave, although according to Sport, Barca can buy him back for double the €5 million fee they sold him for.

All in all, Barcelona deserve an A grade for both their buying and their selling. Close to €123 million was spent, while €32.1 million was received in transfer fees, per Transfermarkt, making it a net spend of €90.65 million. 

If that money helps them challenge for the treble this season and also goes toward revamping the squad when the likes of Alba, Mascherano, Iniesta and Co. need to pass the torch, then it has been money well spent.

Rik Sharma is Bleacher Report's lead Barcelona correspondent. All information and quotes obtained firsthand unless specified. Follow him on Twitter here: @riksharma_.