Messi again delivered at a crucial time for Barca on Sunday, scoring a hat-trick in an entertaining 4-2 win at Deportivo La Coruna to see the club clinch a seventh league crown in 10 seasons.
The Argentina international feels his side, who remain unbeaten in La Liga this season, were deserved champions.
"We were very superior to the other rivals," Messi told Movistar.
"We did not lose games practically, only one in the Copa [del Rey] and, unfortunately, the Champions League, which was unexpected because of how we arrived.
"The truth is it [Barcelona's title] has a lot of merit. It's very difficult."
The La Liga crown means Barca send out Andres Iniesta, who is ending his 22-year association with the club at the end of the season, with a double.
Messi said he would have loved to see Iniesta leave with a treble, but Barca were stunned in the Champions League quarter-finals by Roma.
"We regret it in the Champions League that he cannot go with a treble," he said.
"But I think he goes in an impressive way, a double more than deserved for what he is and for all that he gave the club.
"We wish him the best."