However, in the Champions League, Barcelona crashed out in the quarter-finals for the third year in a row, losing to Roma 0–3 and being eliminated on away goals as a result (after a 4–1 home victory).

Giorgio Chiellini pulled one back for Juventus in the 63rd minute, not enough to keep the Ernesto Valverde era from beginning with a convincing win.

[10] On 29 July, Barcelona defeated Real Madrid 3–2 in their final match of the U.S. tour, winning the United States edition of the 2017 International Champions Cup.

In the 77th minute, Luis Suárez was brought down in the box by goalkeeper Keylor Navas, resulting in a penalty which was converted by Lionel Messi.

[16] In the 80th minute, Real Madrid scored their second through a counterattack when Isco assisted Cristiano Ronaldo, who shot into the top right corner from the edge of the box.

Real's last goal was scored in the 90th minute in similar fashion to the second, when Marco Asensio shot into the top left corner following an assist from Lucas Vázquez.

The first goal of the match came quite early through a Real throw-in the fourth minute which resulted into getting the ball to Marco Asensio, who scored from long range.

Nine minutes after the half-hour mark, Marcelo crossed in for Karim Benzema to control, who finished it with a half-volley into the net which was enough for the win for Real.

[19] On 20 August, Barcelona defeated Real Betis 2–0 in their first Liga match of the season, following an own goal from Alin Toșca and a second within three minutes by Sergi Roberto.

Ousmane Dembélé made his debut, coming on as a substitute for Gerard Deulofeu in the 68th minute; he set Suárez up for the final goal.

Girona captain Aday and goalkeeper Iraizoz inadvertently steered the ball into their own net to give Barcelona a two-goal lead, before Luis Suárez topped off the scoring.

[33] On 1 October, Barcelona defeated Las Palmas 3–0 in a game played behind closed doors at the Camp Nou, due to violence in Catalonia relating to an ongoing independence referendum.

[35] On 3 October, Barcelona joined the country-wide strike called by ‘Taula per la Democràcia’ (Table for Democracy) and therefore the club offices remained closed.

Saúl scored early into the game to give Atlético the lead, but Luis Suárez saved Barça's day with a last-gasp header.

The Catalans maintained a perfect start thanks to an early own-goal, Messi's 100th European goal, and one from Digne, although the visitors did pull one back at the last minute.

Barcelona had a goal ruled for offside and one deemed to have touched Piqué's hand and entered the net, resulting in his second yellow of the night, and his suspension for the return game.

Goals from Messi and Paulinho split the teams in Bilbao to ensure the Catalans stay four points clear at the top of the Liga table.

Suárez, Messi and Aleix Vidal each scored a goal that saw the Blaugrana head into the Christmas break 14 points clear of the defending champions.

A gripping cup first leg ended at Balaídos all square on the night that Ousmane Dembélé made his long-awaited return from injury.

[57] On 7 January, Barcelona won against Levante 3–0, Ernesto Valverde's men kicked off the New Year in La Liga with an impressive team performance and goals from Messi, Suárez and Paulinho.

[58] On 11 January, Barcelona and Sociedade Esportiva Palmeiras reached an agreement for the transfer of Yerry Mina for the remainder of the season and five more until June 30, 2023.

Four goals in the first 31 minutes (2 from Messi and one each from Jordi Alba and Luis Suárez) got the job done early and Rakitic headed in a late fifth as the Catalans cruised into the quarter-finals of the Copa del Rey.

Philippe Coutinho's debut, and goals from Lionel Messi and Luis Suárez brought the Camp Nou to its feet as Barça reached the semi-finals of the Copa del Rey.

Barça equaled a club record by going unbeaten in first 21 league games of the season thanks to a second half comeback win with goals from Suárez and Messi.

Coutinho claimed first goal in a blaugrana jersey and Rakitic added a second to send the Catalans into the Copa del Rey final against Sevilla on April 21[73] On 11 February, Barcelona drew with Getafe 0–0 at the Camp Nou.

Goals from Luis Suárez and Jordi Alba secured three hard-earned points in the Basque Country to match the Club record unbeaten run in La Liga.

[86] On 7 April, Barca defeated Leganes 3–1 drawing level with the joint-record of 38 unbeaten games set by Real Sociedad,[87] thanks to a Messi hat-trick.

[89] On 14 April, Barca defeated València 2–1 with goals from Luis Suárez and Samuel Umtiti that secured the longest unbeaten streak (39) in La Liga history.

[91] On 21 April, Barcelona cruised to their fourth consecutive Copa del Rey title as they beat Sevilla 5–0 at the Wanda Metropolitano.

Iniesta, a World Cup winner with Spain, won nine La Liga titles alongside four Champions League wins and six Copa del Rey crowns.