Aritz Aduriz scored late on as Barca suffered a 1-0 defeat at San Mames in their league opener, while Betis also lost their first match at home to Real Valladolid.
Barca only had two shots on target in their loss at Bilbao last week, and it would be fair to say that it was an extremely lacklustre performance from the Catalan giants on the opening night of the new La Liga campaign.
Granted, Lionel Messi's absence played a huge role in the defeat but head coach Ernesto Valverde would have believed that the team that he sent onto the field had more than enough to triumph. Sergio Busquets and Ivan Rakitic were surprisingly named on the bench, with Carles Alena, Sergi Roberto and Frenkie de Jong in midfield.
De Jong impressed on his competitive debut for the club but Alena and Roberto were both substituted during the contest. Luis Suarez picked up a first-half injury, meanwhile, and the Uruguay international is now facing a period on the sidelines, and the same can also be said for Ousmane Dembele.
Messi returned to training earlier this week, however, and should be fit for the clash on Sunday. The Argentine's recovery has come at the perfect time when considering the issues that Valverde has in the final third. It is still very early in the campaign but another defeat in this match would be very tough to take.
Betis actually recorded a 4-3 victory in the corresponding match at Camp Nou last term, which was the only home defeat that Barca suffered in the league during the 2018-19 campaign. The Catalan giants won 15 of their 19 home fixtures - scoring a stunning 51 times in the process.
That said, the Spanish champions did concede 17 home goals last season, which is more than Atletico Madrid, Real Madrid, Valencia, Getafe and Leganes. Their defence was certainly vulnerable at Camp Nou, although the quality of Messi down the other end of the field often made the difference.
In terms of what is ahead, Barca will finish the month of August with a trip to Osasuna before hosting Valencia in their first match after the September international break. The group stages of the Champions League will also start next month, and there will be pressure on Valverde's side in the European Cup.
Losing both Luis Suarez and Dembele at this stage of the season is far from ideal - Messi's return is huge, though, and Barca will also be looking for more from Antoine Griezmann this weekend after a fairly disappointing performance at San Mames last time out.
Recent form: L
There is no question that Betis would have been looking to start their new campaign with a win at home to Valladolid last weekend. The visitors had not read the script, though, and recorded a 2-1 victory in Seville courtesy of an 89th-minute strike from Oscar Plano.
It was a poor start to the season for the Seville club, although the match did see a number of players make their debuts following summer moves. Big-money arrival Borja Iglesias led the line, while Nabil Fekir, Juanmi, Emerson and Alfonso Pedraza all featured.
Betis are now under the leadership of Rubi, who left Espanyol at the end of last season to take control of Los Verdiblancos, replacing Quique Setien in the process. Having finished sixth in 2017-18, last season will have been seen as a disappointment as they ended the campaign in 10th spot.
It was very much a mixed bag for Betis last season in terms of results, winning 14, drawing eight and losing 16 of their 38 matches. They were only actually three points off seventh-placed Espanyol, though, and will be expected to push for a European spot this season despite losing on the opening weekend.
Securing the services of Fekir during the summer was a huge coup for the club, although they have lost both Junior Firpo and Giovani Lo Celso. Indeed, the former has joined Barca to provide competition for Jordi Alba at left-back, while the latter has moved to Tottenham Hotspur on an initial loan deal.
Goalkeeper Pau Lopez was also sold to Roma for just over £21m, while the likes of Sergio Leon and Ryad Boudebouz have also been moved on, which is an indication of the size of the turnaround at the club.
It is probably a bad time to be facing Barca when considering that the champions lost last weekend. That said, Betis did triumph at Camp Nou last term, while there is no question that the absence of Luis Suarez will leave the team weaker despite Messi's likely return to the first XI.
Rubi's side do have a fairly kind set of fixtures after this game, though, with Leganes, Getafe, Osasuna and Levante to come. As a result, suffering another loss to Barca this weekend would not be the end of the world as there are certainly points to be won during the next few weeks.
Recent form: L
As mentioned, Messi has trained this week, with the Argentine very much in contention to start.
Luis Suarez is out with a calf problem, though, while Ousmane Dembele's hamstring problem will see the France international miss at least the next five weeks of the campaign.
Rakitic and Busquets both started on the bench against Bilbao but should return here, while Rafinha could get the nod in the final third alongside Messi and Griezmann.
As for Betis, new signing Iglesias is a huge doubt due to an ankle problem, while the visitors will also be without the services of goalkeeper Joel Robles following his red card against Valladolid last weekend.
William Carvalho will also keep his spot in the middle of the park, and there will be huge pressure on the Portugal international to deal with the likes of De Jong and Rakitic.
Barcelona possible starting lineup:
Ter Stegen; Semedo, Lenglet, Pique, Alba; Busquets, De Jong, Rakitic; Griezmann, Messi, Rafinha
Real Betis possible starting lineup:
Martin; Alfonso, Mandi, Bartra, Emerson; Carvalho, Garcia; Tello, Fekir, Joaquin; Moron
Head To Head
Last season's 4-3 victory at Camp Nou proved to be the first time that Betis had won an away league game against Barca since May 1998.
The Catalan giants got their revenge in the reverse league game last term, however, with Messi scoring a hat-trick in a 4-1 victory in Seville.
Barca have only lost one of the last 16 meetings between the two teams, while they have scored at least four goals in six of their last 12 matches against Betis, suggesting that there will be goals this weekend.
We say: Barcelona 3-1 Real Betis
It is difficult to look past Barca this weekend. Without Messi, Betis would have fancied their chances of picking up a result. However, the Spanish champions will be keen to put things right following the Bilbao defeat, and there is no question that Messi will be fired up to inflict some damage after missing out last week.