The result leaves Barca 11 points of clear of second-placed Atletico Madrid in the La Liga table - and the division's players will just be hoping Mateo doesn't ask his dad to score a hat-trick the next time he leaves his house!
Messi had scored 16 goals in 18 games against Athletic at Camp Nou coming into this clash and he nearly improved on that tally as early as the fourth minute with a curling free-kick that Kepa Arrizabalaga tipped over the crossbar.
Messi was also involved in the runup to Barcelona's first goal, a shot by Paco Alcacer from near the penalty spot after a low cross by Jordi Alba.
While Barca take on Athletic following their 3-0 Champions League win over Chelsea on Wednesday night, the visitors crashed out of the Europa League on Thursday after a 2-1 home defeat to Olympique Marseilles.
"He is undoubtedly the best player in the world and he shows it every single game", he told reporters after the match.
Messi has scored at least a goal in his last six matches. However, they were rampant in the first half and could have taken a heavier lead into the break as Brazilian midfielder Philippe Coutinho hit the woodwork twice and his compatriot Paulinho struck a post. Only against Sevilla (19) and Espanyol (18) has the Argentine player netted more goals for Barcelona.
Barca are coming towards a key time in the season as they continue a treble bid, meaning Valverde has a nervous wait to see if any more stars are injured on global duty.
The hosts continued to dominate and fine approach play involving Messi and Coutinho ended in Ousmane Dembele firing straight at Kepa from close range but there was no mistake from Messi on the half-hour as he received Dembele's pass and, left all alone on the edge of the area, rifled home.
Athletic dropped to 13th in the 20-team standings.