Messi ended a mini goal drought with a double in Wednesday's 3-1 Group H win at home to AC Milan and the Argentine World Player of the Year will be looking to put a run of four domestic outings for the unbeaten leaders without scoring behind him when struggling Betis visit the Nou Camp.
The 26-year-old, whose season has been disrupted by a couple of minor muscle injuries, delighted his adoring fans when he smashed in a penalty after 30 minutes and sent them into ecstasy when he dashed through the middle and scored with a trademark dinked effort seven minutes from time.
Talk of a Messi crisis dominated the buildup to the game, but his record this term is one most players could only dream of - six goals in three Champions League appearances and eight in 10 La Liga outings.
"I'm calm about the recuperation," Messi said on the UEFA website (www.uefa.com) on Thursday.
"I'm getting my rhythm back bit by bit and I think it really helps to have 90 minutes, then another 90 minutes, back to back so that I can gradually re-establish the tempo and the form I had before," he added.
"This time there have been two injuries really close together and that kind of impact you do notice. But I'm definitely getting past it and I'm happy with my form."
Seville-based Betis, who play at Portuguese side Guimaraes in the Europa League later on Thursday, are mired down in 18th place in the table with just over a quarter of the season played and pressure has been mounting on coach Pepe Mel.
Barca, by contrast, have dropped only two points - in a 0-0 draw at Osasuna last month - and are a point clear of second-placed Atletico Madrid, who play at Villarreal on Sunday (1800).
Barca's arch rivals Real Madrid are a further five points back in third and host fellow Champions League participants Real Sociedad on Saturday (1500).
Real and Atletico are also through to the Champions League knockout round, although Real's 2-2 draw at Group B rivals Juventus on Tuesday again exposed the defensive frailties that have marked many of the performances this season.
Resurgent under Argentine coach Diego Simeone, Atletico swept Austria Vienna aside 4-0 at the Calderon on Wednesday to record their fourth victory in as many games and seal top spot in Group G.
Real coach Carlo Ancelotti has a fearsome attack at his disposal, led by prolific Portugal forward Cristiano Ronaldo, but his defence has been ragged and San Sebastian-based Sociedad have players with pace and skill capable of taking advantage.
The Basque club's European campaign is all-but over after they lost their first three games in Group A and drew at home to Manchester United on Tuesday, but they will be keen to put on a good show at the Bernabeu.
History is against them, however. Sociedad have played 66 league games at Real's giant stadium and have only managed three wins, the last coming in the 2003-04 season, with 47 defeats.
Midfielder David Zurutuza said one of the lessons learned from the meeting with the English champions was that Sociedad need to exert more control and prevent the swift breakaways that yield many of Real's goals.
"Against teams like Manchester (United) or (Real) Madrid you have to help out your team mates more, you have to close down more space and the physical demands are greater," he said at a news conference on Wednesday.
"Both of them like a back and forth style of play and that's what we have to avoid with a more measured and deliberate approach," he added.
- Sports & Recreation