The Argentine featured in his first full 90 minutes of 2019-20 at Camp Nou on Wednesday having only recently recovered from a thigh injury and he was involved in both goals as Barca came from behind to win.
Lautaro Martinez had given the visitors the lead before Messi jinked his way past a couple of challenges and laid the ball off to Arturo Vidal, who crossed for Luis Suarez to smack home an impressive volley.
Messi was then at his dazzling best as he raced forward and advanced past two opponents before cutting inside and setting up Suarez to slot home for his second of the evening.
But the 32-year-old insists that he is not yet fully back in the groove, warning Barca's rivals that he'll continue to improve as he features in more matches through the season.
He told reporters: "I'm trying to keep up, it is the first 90 minutes that I've been able to complete since the beginning of the season.
"I'm happy to have ended the match well, of course I am tired, I am missing the rhythm but like with all the team, as the matches go on I am building that rhythm.
"During the year I am used to playing and keeping up to the rhythm of the game because we can do very little with training. We play every week, Sunday's, Wednesday's... and so it is hard to put in strong training."
Barca have made an indifferent start to the 2019-20 campaign domestically having picked up 13 points from their opening seven games to leave them in fourth place in the table.
It's not been plain sailing for table-toppers Real Madrid either, however, with Zinedine Zidane's side having drawn three times to mean they're only two points ahead of the Catalans at the top.
Then comes the first Clasico clash of the season three days later on October 26, with Los Blancos looking to beat the Liga champions for the first time since August 2017.