For the second weekend running, Real and Atletico Madrid played before Barca and respective wins over Real Sociedad and Rayo Vallecano turned up the heat on the champions.
Luis Enrique's men initially struggled to muster a response as Barca failed to display their usual fluent, attacking style of football at the Benito Villamarin.
However, Heiko Westermann's dismissal for a second yellow card 10 minutes before the break threatened to undo Betis' hard work in the opening period and Barca did get the crucial breakthrough five minutes after the break.
Rakitic had been regularly booed due to his previous association with Betis' fierce rivals Sevilla, but he had the last laugh by tapping in after costly miscommunication between German Pezzella and goalkeeper Antonio Adan.
And Suarez, who had scored eight times over Barca's past two matches, wrapped up the win late on with his 35th Liga goal of the season.
Barca may not have hit the heights they did in 8-0 and 6-0 wins over Deportivo La Coruna and Sporting Gijon in their previous two matches, but they stay top, level on points with Atleti and one above Real Madrid with two games left.
It was Betis who had the better opportunities in a lacklustre opening, Ruben Castro's bending effort was deflected for a corner from which Claudio Bravo smartly tipped Bruno's header over the crossbar.
Barca struggled for fluency and Luis Enrique cut a frustrated figure in the technical area as his side toiled against a stubborn defence.
The visitors saw Andres Iniesta slice wide after good work by Neymar, before the Brazil captain shot tamely at Adan when in a promising position in the area.
Betis were dealt a blow in the 35th minute, though, when Westermann received a second yellow card and subsequent red for chopping down Rakitic.
The numerical advantage should have paid dividends a minute after the break. Neymar picked out the run of Suarez, but the usually clinical forward shot wide of the left-hand post when one-on-one.
Barca did have the lead in the 50th minute, though, after shambolic Betis defending.
Lionel Messi clipped a harmless pass into the area, but Pezzella failed with a woeful attempted acrobatic clearance and the on-rushing Adan also missed the ball to leave Rakitic to tap into the empty goal.
