Atletico Madrid's 3-0 win over Las Palmas earlier on Monday (AEDT) placed a modicum of pressure on Ernesto Valverde's runaway leader and it seemed to weigh upon it in a ragged first-half showing.
Philippe Coutinho made his full debut, but it was a more unheralded January signing, Alaves's Celta Vigo loanee John Guidetti, who threatened the upset with a fortuitous 23rd-minute opener.
Abelardo Fernandez's side remains two points above the drop zone and were left to rue missed chances by the time Luis Suarez netted for the eighth top-flight match in succession with 18 minutes to play.
Typically, it fell to Messi to apply the coup de grace as he curled a delightful free-kick home to spark raucous celebrations.
Barcelona remains undefeated and 11 points clear on its apparent procession to LaLiga glory.