Conceding appeared to wake Barca from their slumber and they were doubly denied by Hernandez seconds later as Neymar went down inside the area and the ball ricocheted towards the Betis goal off Riza Durmisi.
Replays showed the ball clearly went over the line before Alissa Mandi cleared, but La Liga’s refusal to implement goal line technology due to pricing fears cost Barca dearly as no goal was given.
Betis should have sealed the three points when Castro broke clear on goal eight minutes from time, but Ter Stegen redeemed himself with a fine save.
And that miss proved crucial as Messi finally found the space to slip a pass through the Betis defence and Suarez dispatched the ball into the far corner.
There was also refereeing controversy at Espanyol as Sevilla’s shot at moving top lasted barely two minutes when Nico Pareja was very harshly sent-off on top of conceding a penalty for a trip on Pablo Piatti.
Former Sevilla favourite Jose Antonio Reyes showed no mercy to his former club as he converted from the spot, although Reyes did hold his hands up in apology at the travelling support.
The 10 men reacted brilliantly, though, and were level when Stefan Jovetic continued his hot streak since joining on-loan from Inter Milan to sweep home Samir Nasri’s pass after 19 minutes.
Reyes haunted Sevilla once more as his free-kick was headed home by Marc Navarro in first-half stoppage time.
And Gerard Moreno sealed the three points for Espanyol as this time Navarro was the supplier for his headed finish.