The Catalan giants will be determined to make a positive start to their league season but face a tough examination by a Villarreal side that have already picked up four points in Spain's top flight this term.
At one stage, it seemed incredibly unlikely that Lionel Messi would be in the Barca XI for their first league match of the season, with the Argentine signalling a desire to leave Camp Nou in this summer's transfer window.
Messi has ultimately accepted to spend at least one more year with the club, but there have been huge changes this summer with the likes of Arthur, Nelson Semedo, Ivan Rakitic, Luis Suarez and Arturo Vidal all moving on.
Miralem Pjanic has been the major incoming, while deals for Trincao, Matheus Fernandes and Pedri have also been secured, but there has been no Pierre-Emerick Aubameyang or Lautaro Martinez this summer.
Barca's involvement in the latter stages of the Champions League, where they incredibly lost 8-2 to Bayern Munich, means that they are late starters in La Liga, although Koeman's side did beat Elche 1-0 in the Joan Gamper Trophy last weekend and have also played two friendlies this summer.
There is no downplaying the importance of this weekend's clash at Camp Nou, and a number of side stories should make it a fascinating encounter against an extremely dangerous Villarreal outfit.
Villarreal, as mentioned, have already played twice in Spain's top flight this season and currently sit third in the table, having gathered four points courtesy of one win and one draw.
Unai Emery's side finished fifth in Spain's top flight last term, meaning that they will be present in the group stages of this season's Europa League and could be a side to watch in that particular competition.
Villarreal have been relatively busy in the current transfer window, meanwhile, securing deals for the likes of Francis Coquelin and Dani Parejo, while a £15m swoop for Watford's Pervis Estupinan is a signal of their intent.
El Submarino Amarillo have not actually beaten Barca in La Liga since March 2008, though, and have lost six of their last seven encounters with the Catalan giants in Spain's top flight.
Barcelona form (all competitions): W
Villarreal La Liga form: DW
Barca, who were runners-up to Real Madrid in La Liga last term, will be without their number one goalkeeper Marc-Andre ter Stegen until at least the end of October with a knee injury, meaning that Neto is set to line up between the sticks for the home side.
Samuel Umtiti and Martin Braithwaite are also out with knee and thigh issues respectively, but Koeman otherwise has a strong squad to choose from and has a number of decisions to make, particularly in the final third.
Pjanic could therefore start on the bench alongside Ousmane Dembele, who looks set to stay with the club this summer despite being linked with both Liverpool and Manchester United.
Moreno and Alcacer scored the goals against Eibar and are likely to continue as the front two, with Samuel Chukwueze also expected to feature in an exciting attack.
Barcelona possible starting lineup:
Neto; Roberto, Pique, Lenglet, Alba; De Jong, Busquets; Coutinho, Messi, Fati; Griezmann
Villarreal possible starting lineup:
Asenjo; Gaspar, Funes Mori, Torres, Estupinan; Chukwueze, Coquelin, Parejo, Moi Gomez; Moreno, Alcacer
We say: Barcelona 2-1 Villarreal
Villarreal have more minutes in their legs, which should help them at this stage of the season despite the quick turnaround from 2019-20. Barca's record against the Yellow Submarine is terrific, though, and we fancy Messi to be on the scoresheet in a narrow success for Koeman's side.