The Argentine genius played a starring role yet again, bagging his 41st hat-trick as undefeated Barca beat now relegated Deportivo 4-2 to claim their 25th league title overall - and their seventh in the last ten seasons.
Messi was particularly lethal from set pieces this season, scoring seven times from free kicks, including in a decisive 1-0 win against Atletico Madrid that halted their run for the lead in a crucial moment of the season.
The Depor players gave them a guard of honour as the teams took to the pitch, with Ernesto Valverde's men having won the Copa del Rey last weekend before switching their focus to wrapping up the league.
They are only four games from an unbeaten La Liga season.
Following Barcelona's win at Estadio Riazor, Barcelona players wore the shirt of players who contributed to this season's league success. "They won the title, which they wanted, and the guard of honour does not matter for them or for us", Ramos said at a press conference ahead of Tuesday's second leg of the UEFA Champions League semi-finals against Bayern Munich.
Atletico Madrid can no longer catch Barcelona in the table, as they sit 11 points behind with three games to play.
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"We know how complicated it is to win the league, which is why we have to cherish this and celebrate it as we should with all our fans". We know how hard it is to win it and we have to appreciate it and celebrate it.
"We were very superior to the other rivals", he told Movistar.
All of Barca's goals were exceptional but the nonchalance with which Luis Suarez crossed with the outside of his foot for Messi to side-foot home the second smacked of a team yet to lose a league match.
Andres Iniesta, who last week announced he will not return for a 17th season with Barcelona, also has nine titles.
Barcelona-based daily Sport said: "Nothing is better than a double", which had been clinched thanks to yet another intervention by the "unstoppable" Messi.
Atletico forward Angel Correa was sent off with a second yellow card in second-half injury time.
Fourth-placed Valencia hosted Eibar but they could only draw a blank against the Basques.