"But we could lose our next game [away at Sevilla]".
Paco Alcacer scored after only eight minutes to put the hosts ahead when he steered in Jordi Alba's pull-back, before Messi made it 2-0 with a low strike on the half hour mark.
Messi scored his 25th league goal for the ninth consecutive season and took his tally to 38 in all competitions with a finish from the edge of the penalty area.
Barca dominated the encounter and could have had more goals as Philippe Coutinho hit the crossbar twice, and Paulinho too once.
Forward Javier Eraso side-footed home the second goal for the home side in the 69th minute and things got worse for Sevilla when midfielder Pablo Sarabia was sent off in the 84th for picking up two yellow cards inside 11 minutes.
He is one of five players missing for Athletic's visit to Camp Nou on Sunday.
"Carrying on like this will help us reach our objective". "We're not going to tempt fate".
Britain, Russia trade blame over poisoning of former spy
Speaking at the same event in Dubai, Tory former chancellor George Osborne, attacked Labour leader Jeremy Corbyn's response. He added: 'We support exactly what the prime minister said and we condemn Russian Federation for this, condemn them.
But despite his side being on the brink of a third title in four seasons, Valverde warned they would not be taking their foot off the gas.
Just four days after an encounter with Chelsea that was more exacting than the 3-0 scoreline suggested, the intensity understandably dropped in the second half, but Valverde's men were able to keep Athletic at arm's length to ensure they head into the worldwide break in buoyant mood.
- Messi has scored 17 goals in his 19 games at the Camp Nou against Athletic in all competitions.
Second-placed Atletico effectively surrendered their hopes of overhauling Barca at the top, as two late goals from 20-year-old Turkey striker Enes Unal handed Villarreal a 2-1 victory over Diego Simeone's side. "In the first half they were fantastic and showed why they're league leaders".
Earlier, Sevilla crashed to a 2-1 league defeat to Leganes just days after pulling off the surprise elimination of Manchester United in the Champions League.
Ernesto Valverde dismissed the idea that he, as Pep Guardiola and Luis Enrique had done before, would win a league, Cup and Champions League treble in his first season at the helm.